MTN is useless

MTN did a migration, upgrading my data and costing me a extra R220 p/m without my acknowledgement . This happened July 2021. I went into the MTN store at Hemmingsway and Retail Park East London BUT no help !!!! Then phoned customer care and i was told i need a affidavit and case number which i did and emailed it. I have phoned every month complaining and was told it will be downgraded and i will be refunded. It is now March 2022 and still no help. MTN is useless, make promises and never keep them. HELP . !!!