DSTV - Outstanding Balance

Hi, I've switched from DSTV Premium to DSTV compact. I pay my subscription in advance for the year. Now, DSTV is harassing me for R1100-00 Access fee. When I changed packages there were no mention of an access fee, just the full amount I had to pay for the year. Now, according to DSTV I still owe this R1100-00. If they stipulated that in the amount I had to pay, I would have paid it gladly, but now after some months, DSTV comes up with me owing them money. I do not understand the accounting process very clearly. Could someone sort this out speedily? Thanks