Mtn uncapped contract

Took out a uncapped contract for R449 month end June at Centurion branch on a Saturday , when I tried to connect when I got home it was buffering so the next day when back to their office to let them know that the coverage is poor. Monday morning they advised me to bring it in so that they can test it.They rebooted the router which i took it back home with to test but still connection was bad,Took it back to the branch and the supervisor advised that they will call in people from coverage to come inspect at my house if there’s coverage so that I’m not charged for early cancellation because the device is not serving it’s purpose.since then they haven’t contacted me about my case ,I have decided to cancel my contract and they plan to double deduct for something I haven’t used..