Wrongful billing

On the 28th of of May I was a reward by multichoice but later on I was charged for the same same reward, I've been been battling ewith for the last two weeks but they've never been able assist me or they refusing to assist I'm not sure. The reward I was given was to view premium channels and I was told that my subscription will remain the same but to my surprise my bill went up by almost R300 when I inquire they included the reward. MULTICHOICE PLEASE GET YOUR HOUSE IN ORDER BECAUSE IT'S NOT THE FIRST TIME BEING TREATED LIKE YOU GUYS ARE DOING ME FAVOUR.