Dissatisfied customer and now maybe in debt!!!

In December I made an early payment to DSTV and in Jan it was deducted as well, so I was in credit. In Jan the PVR decoder was faulty. I took it in on 17/01/2015 and was given a refurbished one. I paid with some of the credit I had as it was not insured, I also insured both decoders by then It was tested and worked at their offices. I took it home and it didn't work. I had to go back on ***5 - time away from work. They gave me another one and it worked, by then the 2nd one has not been working since, I reported it an to date it is still not working. I then starting receiving messages stating that I owe monies, which I did not. I called and was informed that there were system issues. I received another message stating I still owe monies Ref***, then clarified and said it was incorrect and was then fixed. Today I see R1822.05 has been deducted, for gawd knows what cause I have not been delighted since January! Now I must wait till 13:30 today for someone to investigate and come back to me, then will hve to wait longer for my damn money!!! QA is obviously not doing their job properly otherwise someone would have made an effort to sort this issue out in Jan already!