Telkom is a **** and they rob customers

Telkom is a ****, I called to cancel my contract after the 24th month and the lady who assisted me made a mistake and canceled the wrong contract which I've had for 7 months, there's proof that it was their mistake & she even made notes and all Telkom staff I've spoken to and assist can see and admit that she made a mistake but their billing department insist that I pay the once off 10K device fee because the contract has been canceled and can't be reinstated , I have tried for 2 months to have them fix this and reinstate my account & they keep saying it's sorted but I'm getting calls and messages for this device fee which I am not going to pay cause I did not ask for that contract to be canceled and it's not my mistake so why must I suffer because if I wanted to buy the device cash than I would have , it's frustrating cause you talk to a different agent everytime you call and there's different stories each time but I am not getting any solutions and this will affect my credit score