Terrible customer service

I spoke to somebody back in October and was on the phone with them for at least a couple hours and they offered me a five-year plan at $65 a month with Taxes and fees included in the $65 a month fee. And since that time I have been continually charged more than the $65 a month they credited me on my account last month that was supposed to reflect on this month bill which it did not. I texted back-and-forth with an agent who said it would be on next month bill but when I go into my account it’s still showing that my monthly charge should be $75.99. When I called to try to speak to somebody about this, you’re on hold for close to an hour and today I was holding for about 30 minutes and they hung up on me. You can’t speak to a real person I’ve called multiple times spoke to many different people. They tell me it’s gonna be resolved and it’s not this is the worst Internet service ever