Unfair billing and breach of contract

Last week telkom phoned me to upgrade my phone. I preferred not to upgrade and just keep the phone that I have. The caller then confirmed she updated my contract by removing the amount for the device which has been paid off. I am then only paying for my data every month. The amount she confirmed was R160 pm. This week, the old amount was deducted from my bank account via a debit order. Over two days ago I emailed Telkom support to request that they rectify this. I still have not heard back from them. Email ticket #49480 Also this morning I tried to buy data online via their website. The amount was charged on my credit card but the data was never loaded to my phone. My number is ***. It is against the law to deduct an unauthorized amount from a client's bank account or credit card. It is considered unfair billing and breach of contract.