TELKOM....NEED I SAY MORE!!!!!!

Telkom is the most unprofessional business I have ever come into contact with. I have been a loyal customer for a few years and I have had issues with them debiting my account more than once for the same amount and let me tell you the amount is not small.... I contacted the customer service department (another useless bunch of people), and I needed to update my banking details (which I didn't want to do as I don't trust Telkom with my account information as they have debited my account more than once for one premium), nevertheless I went ahead and updated the banking details and was told that they are not sure if the debit was going to go off the new or old bank account and that I might be charged fees for the debit not going off the old account even though I have updated my banking details. how can such a big business be unable to give me a definite answer and i cannot understand why fees will be charged for this as no other company charges me fees, I need professional assistance that will be able to treat customers fairly, i will not be renewing my contract with telkom as i have had numerous issues.