Instant money voucher-not receiving code

I received a instant money payment yesterday. The voucher number was blocked. I called standard bank and was told a new voucher number is being sent to my phone, which I didn't receive. I called them another 2 times and it was sent each time but I still don't have it. I was told that there is network problems with mtn and must wait 30min but I still haven't received it but I receive sms messages from everyone else. How am I supposed to withdraw my money without my voucher number! !!