Can not change my airtime to data

This is not the first time this month I have problems with vodacom, I'm really start to think to change to another network, I was never before so unhappy with vodacom - what is happening?<br> My problem now is that I urgently need to change my airtime to data on my DATA sim, but when I try to do that I get a error saying I can not do that because I'm not the main account holder - I AM!<br> <br> I phoned customer care on 111 to find out what the problem is the lady Monique put me on hold and then suddenly I must rate the service without being helped. <br> Now the result is I'm using my airtime on the sim for data - so this means it will go quicker than normal. I can not change the airtime to data on *111# because its a data contract so I pay less for data than normal pre-paid numbers.