Ofcom is writing to broadband companies to ask why some people are having to pay to keep old email addresses.
TalkTalk charges £5 a month and BT charges £7.50 a month if customers switch providers but want to keep using their email addresses as before.
Virgin deletes those it gives to customers 90 days after they leave, but Sky lets people keep theirs for free.
Ofcom told Radio 4's Money Box it could see no reason for what one customer called "basically daylight robbery".
Ofcom added: "We're looking at this to consider whether we need to step in and take action."
コメント