@ Home cant get accounts sorted

I purchased a couch at @ home (Part of THE FOSHINI GROUP). It went on sale. So I got the new sale price. Then they had no stock of a colour, so I took the floor item, and got a further discount. Paid the account diligently. Then check all the slips to the account, and saw a discrepancy. I have tried for over a moth to sort out with head office. When I asked for the CHIEF FINANCIAL OFFICERS tel no, thought he could solve problem, then I had some response. Was told they need to get the slips from the store to check. My records show I am in credit. They so NO. Plus i get messages i owe them money and they add interest. After I told them to flag this, that it is under investigation. I have warned them they better not list me with ITC etc, and BEGGED them to assist to get this sorted. Still nothing.