I am so drained

On the 30th of Sept 2015. I took out a new contract, being a third one. I recieved a device Samsung S6 Edge . A few days later the device started heating up even when it is not in in use,so i figured maybe its just a software problem so i took it to Samsung. The technician told me beacuse its a new a device i must take it back to telkom to have it replaced. I took the device to telkom on the 6 of October 2016 they said they have to send it to Pretoria to have it checked. No further contact or feedback was given until i went to the store to enquire. When I got there they said they received the device back and they technicians found nothing wrong with it but if the problem persist i must bring it back i refused to take the faulty device and asked if i can pay for my other two contracts they said if i only pay for the two all my numbers or contracts will be suspended. So I decided to cancel the third one. The cancellation was filled on the 05 Nov 2015.Since then the contract hasn't been cancelled i phone telkom everyday with no help all my numbers don't work and I still receive a bill for a contract i cancelled three months ago. R4000.00 has been debited and no one can explain why.