OpenAir, a company which buys wholesale minutes from mmO2 and resells to its own customers, has filed a detailed report with the telecoms regulator Ofcom, alleging that as much as a quarter of the billing information it was sent by the operator was incorrect. In one instance OpenAir claims that one of its customers, which had 125 handsets running on mmO2’s network, received a monthly bill of GBP28,000 when the correct figure was less than GBP1,000. The report is an embarrassment for mmO2, which just this month was forced to offer call discounts to thousands of its customers after charging them for making calls they thought were free. A computer glitch at mmO2 in July meant that many users who rang the company to check how many free minutes they had left, were given the incorrect information. As a result thousands of customers carried on making calls believing they were still within their all-inclusive bundles. Instead, many were incurring additional call changes. mmO2 has been asked to respond to OpenAir’s allegations.