No communication

We have a data contract with MTN for a wife router, for the last 2 months they have loaded the data incorrectly. We have been trying to get the situation sorted for about a month now to now avail. The consultant we are dealing with at the Oakfields store doesn't answer the phone when we call and if we do get through and leave a message no one phones back. We have also been dealing with the supervisor and she has promised to get back to us which she doesn't do either and is now also not answering our calls. The way this situation has been dealt with has been extremely unprofessional. We are paying for a service and not receiving what we pay for.