Workers refusing service when not in the mood to do so

When i was retrenched i contacted telkom, giving them proof of what had happened so that i could make arrangments to possibly freeze the account as i could not pay without an income. They stated they had no resolutions to the matter and kept billing me but already took away all benefits that came with the contract. I now sit with a R15 000 bill because they were unwilling to help and freeze the account. What am i supposed to do because i have to pay the R15 000 and they still keep billing me every month making it very difficult to lower the number i apparently owe.