EE has been fined £2.7 million by Ofcom for its “carelessness or negligence” in overcharging customers who made calls while roaming in the EU.

Ofcom found that customers calling the network’s 150 mobile helpline from EU countries other than the UK were hit by two separate charging errors between 2014 and 2016:

• Customers charged US prices: Between 1 July 2014 and 20 July 2015 EE customers who called 150 while roaming in the EU were incorrectly charged, as if they’d called the United States. This meant they were charged £1.20/minute instead of 19p/minute. In total, 32,145 customers were overcharged by about £245,700 – an average of £7.64 each.

• Customers charged for free calls: Despite making it free to call or text the 150 number from within the EU from 18 November 2015, EE then charged 7,674 customers for doing so up until 11 January 2016. In total, these customers overpaid by £2,203.33 – an average of 29p each.

While all victims of the second error were promptly identified and refunded by EE, those affected by the first, more costly error were not – with EE initially deciding not to reimburse them until Ofcom intervened.

Of the 32,145 customers affected by that error, EE has now identified and refunded most of them. However at least 6,905 customers remain untraced – in some cases because they’ve left EE. Their £62,000 overpayments have now been donated to charity.

Ofcom insists it’s still “requiring EE to make further attempts to trace and refund every customer who was overcharged”.