ACCOUNT WRONG FOR 9 MONTHS

Ive been struggeling with DSTV since January about my account that cant be sorted. Ive Upgraded to the Premium pakage in December (9th) while the Christmas special of R600 for December and January was running. December 27th I was billed R345 for the compact service on the 8th January a reversal of only R222.58 was done. On the 12 January R759 minus (R160) was added to my account. Ive been phoning the DSTV call centre numouros times and explained this and then be assured they see the problem and that this will be corrected. I phoned I dont know how many times. I went in to the multi choice office in Worcester 3 times as well. I even put this on facebook. Last month I was promised that a supervisor will call me but that also never happend. If they can give me a reason why they keep this diffrence on my account I would appreciate it. I want to connect my other DSTV but if they cant even sort out or at least give a valid reason why this cant be sorted. This is frustrating as I have phoned and drove out more than the outstanding ammount. Please if you value your customers you would at least tell me what the reason is.