Ofcom has fined mobile provider O2 £10.5m for a billing error that double-charged customers for leaving the network.
Around 140,000 of O2’s pay-monthly subscribers were affected by the issue during an eight-year period between 2011 and 2019.
Collectively, the customers paid £2.4m to settle the erroneous final bills, even though O2 had identified a potential problem with the process back in 2011.
In a statement, O2 said that it was “disappointed” by the error and apologised to the customers affected.
Ofcom revealed that 110,000 more customers had been overcharged by a total of £38m, but they fortunately did not have to foot the bill.
O2 did provide a refund to many of the customers, but the telecoms regulator believed that further sanctions were needed.
It revealed that O2 had breached rules that state that customers must receive accurate billing information and that any errors must be amended quickly.
Ofcom enforcement chief Gaucho Rasmussen said: “This a serious breach of our rules and this fine is a reminder that we will step in if we see companies failing to protect their customers.”
The telecoms regulator also advised any mobile users who may have been affected by the error to contact O2 as they may be owed a refund.
O2 has since overhauled its billing process to prevent double-charging – which was triggered during the final month of a customer’s contract – from occurring again.
During the last few years, Ofcom has urged mobile operators to make it easier for customers to switch providers when their contracts end.