Missing airtime

Once again my airtime and data goes missing. Vodacom keeps telling me that it's apps I have on but I literally had my phone in my pocket at the time, nothing was being used. As soon as I can get out of my contract with them I am moving to a new provider as this is really ridiculous. The call centre is impossible to get through to and if by chance you do speak to someone they accuse you of messing up. Sickening!