Telkom dishonesty

I took out a contract with Telekom end of February. The agreed debit order was R355 with No additional data to be added. Debit orders went off as agreed. End of April an amount of R855 was debited. I went into the store to query at the branch at Liberty Mall and I was told to bring in the contract. I waited for the contract but still did not receive it up until now. On the 6th May I requested them to make sure that no additional data is added and I have a reference for that call. Then last night another amount of R855 was debited on my account. I am now at my wits end because I am being debited for something I refused and have been trying in vain to have this issue resolved. Also having this debit order reversed everytime will reflect negatively on my credit profile. I am just GATVOL