When Badr’s grandparents moved from one house to another in April 2018, they had one simple request for Comcast—they wanted the cable company to transfer their Internet-only plan to the new address, with no changes to the service or price.

Badr, who helps manage his grandparents’ account, thought everything had gone smoothly. “We asked to move the exact same service we had in place—just Internet. The customer service rep sent us a text message to confirm, and we confirmed,” he told Ars via email.

Badr’s grandparents’ Internet service was transferred to the new house in Orland Park, Illinois, and the bill remained roughly the same at about $53 a month, at least for a while, he told Ars. It wasn’t until much later that he realized what actually happened. The Comcast rep had “matched the old bill on the monthly cost” but added a streaming TV service that his grandparents didn’t request and never used. The TV service was essentially free for the first year under the promotional deal that the Comcast rep applied to the account, but after the year was up the bill doubled, Badr said. The overcharges continued unnoticed and eventually added up to more than $600.