lack of customer service

I have been debited a second amount 2 days after my debit order date for an amount which I don't know and no one at vodacom I have spoken too is able to see this specific amount. Why is that??? I have been transferred from customer care (082 135) to after sales (***) not to billing as I was told that they are transferring too. I was then transferred back to customer care as they handle billing. Now I have to send proof of payment (which I didn't make) to some email which will be handled in 3 days time. This is the second day I have phoned vodacom with no resolution. Please tell me what I should do to get an answer?