Demand payment but will not supply copy of invoice

I changed my banking details and arranged for my debit order to get cancelled from my personal bank account and to be deducted from my business bank account. At month end Vodacom still tried to deduct money from my personal account but I had not put money in as the account was supposed to be paid from the business account. A few days later money was deducted from my business account. Vodacom is still adament that I owe them money. Instead of Vodacom accounts trying to resolve the problem with me they have just handed it over to their lawyers. I have requested a copy of the account in question but Vodacom does not send it. Eventually the case with the lawyers was withdrawn, only to be handed to another legal firm. I drove to Hyde Park to meet with staff at this company but they have still made no effort to get me a copy of the invoice, and are now saying that I must go to the police station and make an affidavid requesting the invoice from Vodacom. I am entitled to a copy of the invoice and should not be the one running around to resolve the issue. I will also not be liable for any legal costs as it is Vodacom that are not making an effort to resolve this issue.