Not a Telkom customer, yet they take money from my account

Dear Telkom / 8ta,

Thank you for debiting my bank account with R299. This was for the contract I... oh wait, I never signed up for anything with Telkom. Which means that someone **********ly gave you my banking details. Now you expect me to do all the work from my side to correct this. Every time I phone, I am asked to give you my account number - and therein lies the whole problem: I don't have one, because I don't have any accounts with you. Yet you debit my bank account. Please get someone who knows what they're doing and know how to get the details from this contract with only my banking details as reference, to contact me ASAP.