MTN cell can only receive calls

I've upgrade my mtn contract and now I can only receive calls but can not make outgoing calls. I tried the 135 call center and they cant help to solve the problem. They logged two calls for the technical department and when you phone back and they surge the ref no.(***) it does not exist.This was on the 10 of Sep 2020 Then I went to the MTN shop in Brits Mall where the lady was very helpful and also phoned the 135 number they gave us a reset code that did not work. They told me then to call the upgrade section because they made a mistake with the upgrade. I called the upgrade section and they referred me to the contract section. They could not help me and referred me to customers call center. I spoke the whole day on the 15th of Sep 2020 with customers call center who's MTN line is so bad as there service you can't hear when they talk to you. Then on the afternoon of the 15th of Sep 2020 there system was offline and they could not help me. I called the customer service center again on the 16th of Sep 2020 they could not resolve the problem and logged a call again to technical department.(***) I've got a contract with MTN that i pay and do not receive a service from them. This is ***** and i want to stop my contact with MTN. This is the worst service provider ever.