TELKOM BILLING ISSUES

I had taken up a wifi contract with Telkom in 2017, they debited my account for the first few months and then stopped. When I did query with the agent they told me that the account number was incorrect. I confirmed the account number and it was correct and had never changed. A few months later I had still not been debited, I called in again and they said the account no was incorrect, I confirmed and the account number was correct. To date they have not sorted the issue out and exoect me to pay the full ammt. I feel this is not ethically correct as it was not my issue as there was always fund in my account