Hundreds of TalkTalk customers have been locked out of their email accounts after the network took steps to deactivate legacy addresses.
Customers took to the company's forum to complain their accounts had been deactivated, seemingly without warning.
The company appears to have only targeted Tiscali and Lineone email addresses. Lineone was acquired by Tiscali in 2009, which in turn was bought by TalkTalk in 2009.
In the forum, one customer wrote: "Interestingly, I have been swapping emails with Sir Charles Dunstone (or possibly one of his minions?) about the email problems and he has highlighted the problem of spam being sent from disused tiscali accounts. He writes that they have 1700 passwords to change."
Another customer got in touch to say: "The worse thing is that TalkTalk is keeping quiet about this. No service status messages or anything like that."
"And it seems that if you're unlucky enough to be affected, you have to contact TalkTalk yourself to get it sorted out, no doubt using their premium rate phone line. TalkTalk doesn't seem to be doing anything proactively about this."
"It's astonishing that TalkTalk deactivated so many email accounts knowing full well the disruption it would cause; it obviously didn't care."
A spokesbeing from TalkTalk said: "We’re restricting access to a small number of email accounts which we have identified may have been used to send spam, and customers can still access these accounts by resetting their passwords." ®