Vodacom is terrible

Cancelled my contract about a year ago and vodacom carried on debiting my account, when we finally was able to stop the debit order Vodacom said that I was in credit and they would refund the amount. That was about 3 months ago! No one can give me a number to call or mail address, when I do finally get through to a person that tell me to send a list of documents which I have done about 4 times now and still nothing! This is totally unacceptable!