Unfair Billing

I'm not happy of the service, I bought 2x I phone 11 with the contract of paying R800 per month, I phoned them several times to do for me a call limit but they keep on sending me from one consultant to another each day I call them, they do not want to assist me, I was not using their contact numbers frequently, 1st and 2nd month they diducted according to our agreement, end of March they deducted R2808.51 that was my biggest surprise I then reversed it bcs that was not my agreement with them. I'm tired of phoning them. I will end up handing this matter to my lawyer.