Worst customer service ever

I have a refund query with cell c when i called them they clearly stated that they can see that there is a credit balance right but now after days of calling i still get the same email to send proof of manual payment and bank statement which was sent numerous times this is really poor service I wish i never upgraded with them and just ended my service cause the service they giving you wont even get at a tuckshop they just there to take your money and dont give a damn about customers they sell you more excuses the solutions.