Fed Up!! calls being dropped and no one can help

I upgraded to a new contract in December 2018. For the past four days my new phone, Hauwei Mate Pro, MTN network, refuses to make outgoing calls and I have more than enough call time, all I get is a \call ended"error. I have called the call center a few times and all I am told is that everything is fine on their system and that they cannot help me as they dont know what the problem can be. It cannot be the sim card as I can send and receive smsses and my data works fine. I dont know what else to do! Fed up! This is not working for me. I use my phone for work purposes. I do suspect that this has to do with the Caller ID i tried to hide the other day, as this problem started straight after that. I need a response and assistance asap. !!! Surely this is just a setting? I already tried the call barring codes to cancel any possible barring. Doesnt work.