MTN - completely pathetic

I took out a new MTN contract in June 2019. On 6 February 2020 MTN changed my contract to a BUSINESS contract without consulting me. I have now been struggling for over a month to get this sorted out as the store are unable to assist me as this is now a corporate account. I have contacted *** (reference ***) without luck. I have sent an e-mail to *** (reference ***) also with no luck. Been given numbers *** and *** also without any luck. Not sure what to do next, as they seem to be completely *********** when it comes to help customers. I expected better service from a company I have been with for 20 years.