Data and airtime ******!!!

I am really getting annoyed with the fact that either my data or my airtime disappears. One already pay so much for a contract and then one must forever buy data or airtime. Is there no way that I can see how is it possible that my airtime is being used without me making calls. I have data on my phone then i would get an sms saying i am on out-of-bundle rates. How is this possible. Other times the airtime just disappear without me knowing anything. Having prepaid is not an option because i will forever have to top-up, but now even with having a top-up contract i am paying more than i used to.

I have tried to access their site to complain, but even that is not working. Doesn't help to go to the shop itself as they will either insist in making few changes on the phone settings or say that you are using the data on social media or something.

In the evenings i switch of my data as i have wifi at home. This morning when i switched it back on my phone is using my airtime, because apparently my data is depleted, but when i checked i still had 100MB.

Can vodacom please tell me how they check and manage this, because at this stage i am believing that they are not worried at all and just enjoying to steel our money.