NO service, just high cell phone bills

I have been trying to find out for the last 2 months why my cell phone account has almost doubled. The Mtn call centre does not exist anymore, nor have they answered any calls or emails of mine since January. The online \self help"keeps giving errors and no information. I requested cell phone insurance in Dec and it's only been activated this month. I have been into the hillcrest branch to try and see why my account is so high. They could not help me on the day but promised an email response within 20 working days. That was over a month ago. I expressed my dissatisfaction and queries to Unity at Mtn \""customer service\"" 3 weeks ago on 2 occasions and she has still not come back to me. So"