Incorrect Billing for wi fi router after 24 months

I have a data contract which was for a period of 24 months - R 99 per month. About two months before the upgrade, I was phoned numerous times by the Call Center to tell me I'm due for an upgrade. Each and every time I told them I am not interested to have my contract upgraded. I was told the contract can carry on as is, at a lower premium per month as my device was fully paid up by the 24th month of the contract. I was happy with this suggestion and said I'll have it carry on at the lower premium. This has however not happened. I am still paying the full R 99 still each and every month now. It's now two months after I was due for the upgrade that the full R99 has been taken off my account each and every month.

To try and phone the Call Center is useless, and I do not have the time and energy to go to the Telkom outlet, just to be turned away.

I really don't appreciate this bad service and if it cannot be rectified, I want the contract to be cancelled in full!