MTN is the worst

I have had enough with this network provider. I mean I am complaining to them about my disappearing airtime and they are telling me the Same story that i am calling an international number and i am always telling them the same thing, that i did not call any international number and that no one uses my phone except for me. On all occasions they are always telling me that they are unable to assist me. I am really ****ed off. M tired of MTN