Accusing me of owing them money

In January 2013 I have cancelled My cellc contract and have paid them up in full, I took my deposit slip to the Store In Mitchell's plain Promenade and that is where the assistant took the slip and then cancelled the contract, In June last year I went to a store in KC to apply for contract only to find out that I owe them money, first I was told a R300.00 then R150.00 and then R50.00 which to me was stupid and wrong, I then went to promenade store , where I got the most horrible service EVER! I returned the Saturday to the store where by the Store manger Tanya could not assist me , I then Escalated the problem to the Area Manager Jeffrey Swona , we then emailed each other (EMAILS I STILL HAVE) he then told me the matter would be sorted, only for me to try and apply online today and get a consultant call me and told me that I do not qualify because I woe them Money... I dont owe them Money and want them to do something about this... ASAP