Millions of Verizon email account holders — those with addresses  — will lose their emails and contacts if they don't shift over to Verizon-owned AOL, the company says. email addresses can be retained through AOL, so that longtime users don't have to change them. But they will have to follow instructions contained in a link that Verizon will email to them.

There are about 4.4 million account holders, about 2.3 million of which are considered active by Verizon. Subscribers enrolled in these accounts through Verizon's legacy DSL service and Fios.

The telecom giant now deems its AOL subsidiary, formerly America Online, a better email platform and is exiting the email service, company spokesman Raymond McConville said Tuesday.

Verizon also has reached a deal to acquire troubled internet giant Yahoo, which also runs an email platform with millions of accounts. Verizon expects to close on the Yahoo deal this summer.

"This allows us to focus on what we do best — providing the best TV, internet, and voice services out there," Verizon said in an April statement on the corporate website informing customers of the pending changes.

"We stopped issuing new emails a few years ago," McConville said.

Verizon customers have 30 days to take action after being informed — by email — about the need to shift to AOL or find another service such, as Gmail or Outlook. The company will automatically transfer email account information from the current account to AOL, McConville said. But if an individual chooses to go with an outside email service, such as Google, they will have to transfer the information manually.

Details about the changes can be found at Verizon's corporate website. The information was first posted on April 21 and said Verizon would continue notifying customers over the next several weeks. On Tuesday, McConville said Verizon is in the midst of the changeover.

Customers must wait for the notification to switch.

"You have to wait to get the link because it is not generic," McConville said. "It is personal to you."