Telkom no assistance 9 months later

We have been receiving no assistance from Telkom. In October last year my husband migrated to a new contract, the old one was not cancelled and they have been deducting 2 contracts from his bank account. We have been going into different branches sitting in long ques, phoning and sending emails with no assitance 9 months later. We have even thought about stopping the debit order, but they threathen that his credit name will be bad. I am very unhappy. What recourse can we take against them?