VODACOM DOESNT GIVE A DAMN

what can be done to stop Vodacom from *****ing data--?? I took screenshots from data available and also airtime - the so called shake every day competition where you receive data and minutes-- I phoned a Vodacom nr talked for 1.5 min ,dial the USSD code again and again .just to see they took the call from my monthly subscription and NOT from the minutes and data you "won" in the competition. - also downloaded a total of 21 mb from internet , check again my USSD and again another 20 MB was missing - can someone maybe tell us what is to be done ? All of my friends are complaining about the exact same thing and also lots of data that just disappear --