Won't take responsibility for my missing airtime

This is not the first time my airtime has gone missing. This time i finally decided to call and complain, but they tell me their system tells them I was using out of bundle internet, when I know for a fact that this isn't true as I turn off my data as soon as I receive a message warning me that it is almost depleted. It is also not true that it could have been app updates as those only update if I'm in a Wi-fi hot spot.<br> <br> So my airtime is gone, for about the third time, and they are trying to suggest that it's my fault. I have had my phone for about a year, and am quite sure that I know how to use it by now, I have never lost airtime until recently. To suggest that I can't tell when my data is running or not is such a lame way of not taking any responsibility. I could understand if it happened once (which is why I didn't call when it happened the first and second time) but to suggest that I could make the same mistake so many times is pathetic.