UK telecommunications provider BT Group is facing a lawsuit over claims of overcharging customers, which could cost the company almost £600 million ($815m). Justin Le Patourel, founder of Collective Action on Land Lines, or Call, said on Sunday that the group had filed a claim with the Competition Appeal Tribunal. The suit was reported earlier by <em>The Sunday Times</em>. In 2017, Britain’s telecoms watchdog Ofcom found BT was overcharging landline customers since 2009. As a result, the company was forced to reduce monthly costs for customers by about £7 each. But they were not compensated for the previous eight years of overcharging, Mr Le Patourel said. The affected consumers were more likely to be old, on low incomes and vulnerable, Call said, quoting Ofcom. “We take our responsibilities to older and more vulnerable customers very seriously and will defend ourselves against any claim that suggests otherwise,” BT said in response to the suit. The telecoms provider said it offered “discounted landline and broadband packages in what is a competitive market". Current British laws state it is not possible to make compensation claims for overcharging all the way back to 2009, so Call is seeking damages from 2015. “This makes the claim worth £589m, comprising £200 to £500 for each of the 2.3 million affected customers,” the group said. People affected by the claimed overcharging bought a BT landline but did not take broadband from the provider, Call said. Mr Le Patourel is also seeking compensation for consumers who were excluded from the 2017 price cut, but who he says are still being overcharged. These clients had subscribed to a broadband service and a landline, but not in a package.