Mtn *****

I upgraded my contract in June 2020 and was over charged for the month of July and August. I called to query the high bill and was told that this was due to a new system that mtn has changed to. I logged a complaint and was told someone will contact me in 7 days.2 months passed and there was no contact. I called again and was told that my complaint was resolved. They amended my September bill but not July and August. This ***** charging me a higher amount when my contract clearly shows a different price .