I store and MTN, I’m tired of doing your admin! Sort it out! Activate my phone line!

I can not get a hold of the I store in woodlands mall! I upgraded my MTN contract trough them on the 14 th of February 2020. They have yet to send my new contract to mtn, I am losing business due to this! Mtn has cut my ability to make and receive calls. I downgraded on my contract, mtn now wants to charge me R600 a month more. For a contract that I didn’t sign. I have been trying to get a hold of them since March. I store woodlands mall and MTN,Please advise! I am really tired of having to do the admin for the big companies! They do as they please.