Out of Airtime

I have been recharging my cellphone since yesterday, and MTN only allows me one call with my airtime that I paid for then the next thing I'm on their free mtn to mtn calls and with no airtime. How possible is that with just one call and hardly staying a minute on a call. Right now I purchased R30 airtime via cellphone banking as I attempting to make an urgent call with my airtime, I'm told I've ran out of airtime!!!! So I called their Call Centre,Phindile at their call centre tells me to wait an hour or two as their system has not updated that I bought airtime. REALLY MTN THIS IS PATHETIC!!!! MTN has failed with incorrectly billing people with contracts now it is aiming at pre-paid customers. Taking this up as far as possible, as for your systems not updating, how is that my problem. I bought this airtime with my money not on some I owe you ****.