Double billing

It has been over 2 weeks now and I have not been reimbursed by Vodacom for the amounts that they double billed me. R2720 and R610 were the amounts billed in error. I have made 5 visits to the Vodacom store and the branch manager can't resolve the issue. I have given them my bank statement and still no credit into my account. This is absolutely shocking! Shameel, who do I have to talk to to get my money back!!! Also, commitments to credit clients double billed should not be made if you don't deliver on the commitment..