CANNOT MAKE CALLS NO FEEDBACK - INVESTIGATION PENDING

For the past two weeks I am having trouble phoning one MTN number, I have called into the call centre on several occasions and was advised everytime that there is a Network Problem, I called in on 3 April 2018 and was told the same story, there is a Network problem, I have advised the consultant that this cannot be possible as I can call all other networks and other numbers even on the MTN Network. The consultant then advise I should dial ##002#, which I did, I could make once call to the specific MTN number and thereafter I had the same issue where I could not dial the number. I called on Friday 06.04.2018 where I was informed that the matter is being investigated. I then called again yesterday 10 April 2018 where I was informed the ticket is still open and being investigated? How long can this investigation take place, I am sure that they do not even know what the problem is? This is pathetci service from MTN, definately the network with the worst service and highest rates for calls, and data!!!!! Fed Up, really looking at chaning all our contracts with MTN. My ref number ********** 83