Yesterday I heard from not one but two Comcast customers whose supposedly resolved disputes with the Philadelphia company have come back to bite them - after an assist from Comcast's PR staff, offered when they wrote to the Inquirer to complain. Even the worst companies tend to be on their best behavior when a spotlight is shining.

So what's up here - an attack of Zombie Comcast Bills? Comcast seems like a company with a bigger mess on its hands than it admits or is able to fully and effectively handle - though in an update Friday morning, a Comcast spokeswoman assured me that both these cases have now been fully and permanently resolved.

When I first told his story Sunday, Wayne lawyer Edmond Tiryak thought his problems with his former cable and broadband provider had finally been solved. He'd been fighting more than two months to get a $215 refund - owed, he said, because the company had billed him erroneously even though it never actually managed to connect his new service for weeks after he moved.  The last straw was a $215 bill for service never rendered. Before he contacted me, Tiryak had called Verizon for broadband service - an option he was lucky to have - and had written four increasingly frustrated letters to Comcast cable-division president Neil Smit

After the PR staff helped, Tiryak thought his small consumer nightmare was over - confident the charges had been zeroed out as promised, in part because the last assurance he got was the first to include a person's name and phone number. But you can always count on those zombie movies for yet another twist. Yesterday, Tiryak got a formal debt-collection letter - now for $292 - from Southwest Credit Systems in Carrollton, Texas . Tiryak wrote: "You believe these guys?"

No, Ed, I really don't. But I got a nearly instant reply from the PR person who had tried before to help, and who may feel like a character-in-distress herself. Lucky for her, her credit record isn't on the line.

In case you're wondering about loose plot ends: Tiryak tried the phone number left last month on that reassuring voice-mail. He said he got no answer - just weird electronic sounds - on several attempts.

(UPDATE at 11 a.m. Friday: A Comcast spokeswoman says the collection on Tiryak's former account has been canceled and will not affect his credit, adding that the problem was fully resolved Thursday evening after I forwarded his "you believe these guys?" email, and had actually been addressed more than a week ago. So why the collection letter dated March 5?  "His collection was being processed simultaneously with the resolution," she says.)

Ambler resident Sara Hertz hasn't been threatened with collection - yet. But she faced an Attack of the Zombie Comcast Bill, too.

Hertz first wrote me in January, after I told the story of Louis Moravec and Susan Thauer, a Philly couple who had been unable to get broadband and cable installed - or Comcast's effective attention -- for three weeks after a Christmas-week move, despite what they said was more than 50 hours on the phone, much of it on hold, and  various other screw-ups. (Unlike Tiryak, they didn't have the option of Verizon in their neighborhood - if they wanted broadband, they were captive customers.)

Like dozens of other customers, Hertz offered her own tale of Comcast woe in response:

If you are looking for another chapter to the Comcast customer service saga, I would be more than happy to help you.

As a teaser, I returned all my Comcast equipment and cancelled all of my service in November. Comcast owes me money. Instead, I am billed monthly and Comcast now believes that I owe them more than $600. I just got off the phone with them to attempt (once again) to address this and was told that their billing system was down and that I would need to call them back in two hours.

Hertz added: "This is actually the latest of more than a year of errors and confusions on Comcast's part, so if you need more fodder, I would be happy to share."

I can't write about Comcast complaints all the time, so I thanked Hertz and moved on. But after Comcast offered to help Inquirer readers with service or billing problems, I volunteered to forward her email. She wrote last month:

My situation is not yet resolved. After getting my bill "down" from my owing them $600+ to their owing me $48 (all for service I cancelled in November, 2014), Comcast is now saying that I owe them $50. I haven't mustered the energy to call and re-engage with them on this yet. So yes, I'd be happy to have my issue forwarded to them.

Several days later, I was - - Hertz's hero:

I can't thank you enough for your help with Comcast. I've now had two(!) calls from staff in their complaint escalation department. Both told me the same thing: they've reviewed my account and are zeroing out the balance. While I'm pretty certain Comcast does actually owe me money, by this point I'm so relieved to be rid of them, I'm happy to call it a tie. ... I'm proud to say I've benefited from your influence.

Ha! Influential isn't a word I'd use to describe my role here, but I'm reasonably good at making use of the "observer effect": the change that can be brought to bear on a situation simply by letting people or companies know they're being observed.

That doesn't work with Comcast zombie bills, it seems. Or maybe it's just that words like influential have squishy meanings - like, say, zero, which apparently means something different to Comcast than to most people.   Hertz wrote me yesterday:

It turns out that the Comcast account issue I thanked you for helping me resolve a few weeks ago has not really been resolved at all.

Last weekend, no fewer than four Comcast staff from the "customer escalation team" called me to let me know that my account was now clear and that I no longer had a balance of $50.04. I did ask one representative what had happened to the credit of $48.20 I had been told I had in a January call and was told that there was no record of such a balance or conversation. I agreed that we would just zero this out.

Imagine my dismay when I received a bill on March 2 for the sum of $1.48.Of course, this is totally unacceptable and contradicts what the multiple callers had shared with me. On Tuesday, March 10 I contacted the special, super-secret customer escalation phone number and left a voicemail for "Maria", one of the reps who had previously contacted me. I provided all my information and Maria's voicemail promised me that she or a colleague would be in touch with me within 24 hours. I was flabbergasted when I did not hear from anyone within that given time period, so I called again on Wed., March 11 and left a detailed message with the general customer escalation team voicemail. Again, their message assured me that someone would be in touch with me in 24 hours. I am still waiting.

Yours in frustration and despair,

Well, Maria? PR folks? Mr. Roberts? Aren't you a little frustrated, too? Let's note that Hertz actually believed she was owed money, and was willing to write it off. You're demanding a buck and a half?

(UPDATE at 11 a.m. Friday: A Comcast spokeswoman says the last charges - she says $1.46 - were removed Friday morning from Hertz's account.)

Comcast has made it clear that it wants to improve its reputation, as my colleague Bob Fernandez has reported when recounting some recent Comcast gaffes.

Here's a simple tip: We all know it shouldn't take an outsider's intervention, and the risk of more bad publicity, to make you solve a problem with a customer. But if it does, make sure you keep your Zombie Guns at the ready. There's no one more frustrated and angry than a customer who thinks a problem has been solved, and then gets dunned by a collector.

For other avenues of complaint, check out my February column here with links to the Philadelphia franchise authority, the cable folks at New Jersey Board of Public Utilities, and the Federal Communications Commission, along with instructions on how to locate other local franchise authorities.

I have to warn you now, though, that light-handed federal and state regulation of cable companies pretty much means they all just do what I did: forward the complaint to Comcast and hope for the best.  I can't guarantee they're zombie-free.