Exactly the same here: We had Comcast Business for at least a decade, and cancelled it ~Oct after switching to city fiber. They wanted me to ship back the equipment by taking it to a UPS store, didn't have to package it up or anything, just hand it to staff.
I took photos of the gear in the UPS store. We worked for a few months with them to try to get it cancelled after that, eventually they said we didn't ship back all the gear, there were 2 wifi boxes we didn't return. We never had Comcast WiFi. We made a couple more back-and-forths saying this, and eventually they relented, but during this time I think we were charged $600-900 bucks (2-3 months of service) that we couldn't use (because we returned the modem) but they wouldn't cancel because we still allegedly had the WiFi gear.
I took photos of the gear in the UPS store. We worked for a few months with them to try to get it cancelled after that, eventually they said we didn't ship back all the gear, there were 2 wifi boxes we didn't return. We never had Comcast WiFi. We made a couple more back-and-forths saying this, and eventually they relented, but during this time I think we were charged $600-900 bucks (2-3 months of service) that we couldn't use (because we returned the modem) but they wouldn't cancel because we still allegedly had the WiFi gear.