DSTV IS A ****!!!

In March 2019 I was offered a R250.00 Compact Promotion, I upgraded to Compact and the discount was granted. Now on the July statement, there's a R168.00 additional amount that has been added to my bill. When I called the Call Centre, I am told the discount was not supposed to be granted. What the hell is this???? Why was I granted the discount in the First place?????? I am disputing that amount! I don't have it! What you're doing is not legal!!!! You can't offer me a discount and then take it away THREE MONTHS LATER! And expect me to pay!