MTN Service delivery

I recently took out a new contract from MTN (6/7 July). Since I'm using the contract a lot of numbers are unable to phone my number. I reported it to MTN via customer care and the gave me options like restarting , remove the sim and reinstall but still it persisted after varoius time talking to customer care there were no fix to the issue. I've email customer care all respond I get if asked is saying the case is still open. It's more than one month and I have to pay the full amount on my account for half of the service