they charging me but can't tell me what for

Every month you keep charging me random amounts for what you call \remaining charges""; why are you charging me; how long have you been charging me these amounts? Do you just guess these amounts? <br> I want my money back with interest; I have 4 lines with you; one would think you wouldn't rob me since I am a loyal customer.<br> Now I regret choosing cell C;Maybe it's time to take my lines with other service providers.<br> <br> You increased the monthly fee and on top of that you ***** money from me monthly."""