EE customers have been sent billing statements amounting to tens of thousands of pounds after falling victim to a data roaming glitch.
In some cases, account holders have discovered eye-watering charges on their online accounts, while others said EE had blocked their phones due to the system error.
The issue, which started last week, has affected users travelling in America, Canada, Mexico, Australia and New Zealand. It meant some £10.44 data passes for use abroad had failed to activate.
