Data but unable to use

MTN called and I took out a new contract. Specifically asking I want to also be able to make calls and want something similar to my previous contract. I only have a data contract HOWEVER although my balance shows I have data I am unable to use my data again today. This also happened when I just got the new contract and it took me hours of phone calls to get someone at MTN to do something so that I can use my data. Why they need to refresh my line again today is a mystery. Stating I have to wait 30 minutes. This is unacceptable as I need to authenticate payments for work.