UNSOLVED BILLING PROBLEM

I entered into a contract in 2024 received a new phone and I bought a new watch. The contract ended in Jan 2026. I upgrade WITHOUT A NEW DEVICE. I am now supposed to pay R246 per month but I am still being billed for the watch that has been paid off long ago as well, I have been sending emails for the past two month already and they just don't answer my questions and keep on billing me for the watch. I tried to phone but that is impossible to speak to a person as it is automated answers without a human being working there. I have no idea how to resolve this matter.