MTN no call

I have an MTN contract for about 20+years. The other day when I tried to make a call to Mozambique, I received a voice message that I must 1st load air time. This is rather strange as I don't have pay as you go, but a contract. So I refereed the matter to MTN and received the following 2 replies:

Thank you for emailing Customer Care. Kindly advise when you have airtime and you experience this kind of problem as we cannot be able to check on a balance that is no airtime. We trust that you find the above in order. Kind Regards, Thembisile Sithole Customer Services MTN SA Reference Number: ********** 7 Good day Johan, Thank you for emailing Customer Care. Kindly be advised that you do have airtime that is the reason you cannot be able to make out going calls. We trust that you find the above in order. Kind Regards, Thembisile Sithole Customer Services MTN SA Reference Number: ********** 7 My understanding of the English language is fairly good, yet I cannot for the life of me understand what MTN is trying to tell me. O)nly that they seem to be contradicting themselves. What bothers me is that a company the size of MTN cannot have an effective Customer Care program up and running.