********l debit to account

A double payment went off my account. Trying to query this with Telkom is impossible as one cannot get a hold of any customer service officer. Today went to local branch only to be told that it is due to a upgrade. This was not explained and no where did I sign for the additional amount debited to my account. Telkom agent says he cannot explain to as why it has been done without explanation and I should come back in a weeks time to ask the original agent. Seriously the customer service is lacking big time