Dstv discount that I have to payback

Last month they gave me a discount on my dstv compact and now they say I must pay my monthly premium plus the reversal for the discount that they gave me last month. I didn't ask for discount from them they decided to give me discount now I must pay R570 for dstv compact. Please fix your problem before I move to Netflix. I won't pay for the discount that you decided to give me