Airtime Goes Missing

I'm really fed up with vodacom, I bought R30 airtime and and withinin 5 minutes my airtime is gone, i only sent 1 sms and when i check my balance it's all gone im left with R1.24 like really, when i call them they tell me that it must be internet how the hell does the internet work when my data is off and the most irritating thing is that whenever you have a problem all they can tell us is that it's internet that is taking your airtime, they will never give you any other excuse and how the hell can airtime run out so quickly. This is the very same reason that made me change my son and mom from vodacom to another network because the is always issues with airtime. Even when you buy data it never lasts because they charge R2 per MB. AT this point in time in really irritated client if i may say i want nothing to do them. Worse the contract that my fiance has app**** for me as i gift we going to cancel it i would rather he take it to another service provider that having to deal with this **** everytime.