T-Mobile denies it was hacked, links leaked data to vendor breach. T-Mobile has denied it was breached or that source code was stolen after a threat actor claimed to be selling stolen data from the telecommunications company. “T-Mobile systems have not been compromised. We are actively investigating a claim of an issue at a third-party service provider,” T-Mobile shared in a statement to BleepingComputer. “We have no indication that T-Mobile customer data or source code was included and can confirm that the bad actor’s claim that T-Mobile’s infrastructure was accessed is false.”.