FALSE ADVERTISING R249 MTN home WiFi

Mtn has been running an unlimited home WiFi month to month contract from R249(100mg @10mpb then 2mpb after) I app**** for the R249 month to month contract then was called by an agent to pay just over R250 using a certain link she sent. The rented router and sim card was delivered by DSV mid June. I was expecting the debit order of R249 but instead R481😳😳 to my surprise was debited from my account, naturally I reversed it as I know nothing of such an amount .Tried to get hold of MTN on Facebook, sent 3 email on separate days and called 135/083135 unsuccessfully. Eventually I called using the mtn sim and went through to a "champion" as they call them. She told me it was a shortfall of R7__.00 that was payable at the beginning of contract. I told her that it was never stated to me that I will be paying more than R249 cos had I known I wouldn't have even taken the contract at all.I asked for the manager to call me the following day cos it was at night. I have never received a call from anyone at MTN. Now (17/07) they've cut the service and my kids are sitting with no WiFi in the beginning of their school 3rd term. There are many more networks offering this affordable WiFi, I could've joined any of them instead of this frustration. I need help to get a call from mtn or any communication that'll solve this mess once and for all. There's a bad business relationship already and would gladly cancel anytime.