Mobile phone group Giffgaff has been fined £1.4 million by the industry watchdog for “unacceptable” billing mistakes after it overcharged around 2.6 million customers.
Ofcom said Giffgaff – which is owned by O2 parent Telefonica – overcharged customers up to a total of almost £2.9 million over nearly eight years.
It found that Giffgaff had been overcharging customers who bought its pre-pay bundles of voice minutes, text messages and data – called “goodybags” – between May 2011 and February this year.
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Delays in applying goodybag bundles to accounts meant that voice calls and data were wrongly initially taken from pre-paid credit, meaning customers were charged twice.
Giffgaff has already refunded around £2.1 million to affected customers, but in cases where it has been unable to trace customers due a refund, it has donated the money to charity.
Ofcom said the fine – which will be paid to the Treasury – was reduced by 30% after Giffgaff agreed to settle and had reported the mistakes to the regulator.
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But Giffgaff was hit with an extra £50,000 penalty for failing to provide accurate information to two requests by Ofcom during its probe.
Gaucho Rasmussen, director of investigations and enforcement at Ofcom, said: “Getting bills right is a basic duty for every phone company.
“But Giffgaff made unacceptable mistakes, leaving millions of customers out of pocket.
“This fine should serve as a warning to all communications providers: if they get bills wrong, we’ll step in to protect customers.”