Overcharged

I'm having problems with telkom and Im not getting help from their store even when I call the call center. I have a contract with them for my pocket wifi, they supposed to deduct R99 every month. Last month they deducted R162 and this month R189. I went to their store in promenade Mitchell's plain and they told me to phone the call center coz they can not help me. When I called the call center I was told to give my number and they will call me back in 2 minutes which they never did. I went back to the store and they told me I must call again and demand my refund bcoz the call center was at fault. I did the same thing and again I was told to wait for a call from them and I'm getting inpatient now bcoz they're not calling its almost 5days going back and fourth.