O2 customers get three days free for network failure Overall, a third of O2"s more than 22 million customers, or around 7.4 million, were cut off, the firm said. All customers, including those unaffected by the failure, will also get a £10 voucher to spend with O2"s "Priority Moments" loyalty scheme. It hosts special offers for restaurants, cinemas, clothes shops and other items. Not all customers were cut off because mobile phones "check in" with the network as a security measure only periodically. When the system handling that process failed last Wednesday, devices were gradually disconnected over a 24-hour period. Engineers worked through the night to restore basic 2G call and text services on Thursday morning, and 3G mobile internet access at lunchtime. As the outage continued O2 faced a storm of criticism on Twitter, including from high profile customers such as the BBC newsreader Huw Edwards, but it won plaudits for its contrite and humorous responses. Today's apology however follows widespread calls for compensation, including from the consumer campaign group Which?. An online poll this week claimed that a third of customers were planning to leave O2 as a result of the breakdown.