MTN bad service

I did an online upgrade on the 4th of March, received order no., just to be informed that it was cancelled, was told to apply again, so I did on the 9th of March just to be informed again that it was cancelled, called customer care, and the lady says that the system does not give a reason for cancellation, this is ridiculous, how can they not provide me with a reason, I have been using MTN network since 2003 and never had a problem