Data and Network Issues

I would just like to find out, I've loaded 60MB last night on my however, i just disappeared when i didn't even open any apps or downloaded any apps or whatever and there were no pending downloads. I need to know what happened to the data that I've loaded. Why did my data disappear without me using it. I've loaded 30MB 1st when I checked my balance after a while it showed 0MB, I then loaded another 30MB I opened whatsapp and when i checked my messages were not being delivered, when i checked my balance again, it showed 0MB.

Can someone please explain what is up with the Vodacom network, because messaged are not being delivered at times on a daily due to network connection. Is there problem with the network?

Please provide feedback on this asap and can I just have my unused data loaded it might not be much, but it is needed.