horrible Internet, Internet service

Been with T-Mobile for over two years had problems left, and right my services in and out all the time they keep blaming the tower and my modem. This is my third modem first one they charged me and lost it in their warehouse for over two months. Keep saying they're upgrading the tower for the last year and a half every time they give me a credit for my Internet, not working they raise my bill up I am supposed to be paying $50 a month and my bill is $60 $80 $175 $120 all different amounts every month I was set up on auto pay. They automatically take me off and then charge me extra to make my payment, does anyone else have this issue?