Poor Telkom Customer Service

I did a migration with Telkom Canal Walk Express and requested the agent to debit the old device on installation which he did as he showed me. The debit went on fine for 3 months and then out of the blow telkom debited R2500 from my account and when I call the call centre I was told it's for the old device fee which I requested it to be added on to my current contract. On logging a case I was told by telkom there is nothing they can do to help me. I don't have to money to pay them as I did not make plans for R2890 to be taken off my account. I need telkom to fix this asap as they are threatening on suspending my account which I have been paying for more that 4 years now. Furthermore, they are still deducting R170 for the old device from me and trying to debit it in full as stated above. Very disheartened customer.