How To Speak to an American that can actually help?

I am so sick and tired of dealing with outsourced customer service agents that do not have any REAL ABILITIES to fix what is wrong. They tell you one thing and then don't do it. You go back to talk to them and then say they have limited abilities and can't do it. Here are my issues that I need IMMEDIATE assistance with. 

1. For YEARS I've been paying for the highest internet speed package when it was offered to me. Starting about two years ago I began having terrible intermittent connectivity issues. I called and chatted over and over only for the basic "reboot modem" resolution. Until finally, one day, there was one smart person that decided to check my speeds. They noticed I'd been paying for the highest speed but getting nothing close to that and the reason was because my modem was outdated and incapable of producing said speeds. So for YEARS I'd been getting ripped off. I requested to have 50 dollar per month credits each month on my bill for a period of at least one year to compensate me for that huge amount of money I'd been paying for years and not getting the service. I was told they submitted a ticket for that blah blah. I have no seen the credit to date and every time I go to the chat I get told they can't do it. 

I DEMAND some sort of compensation for the two years I was not getting a service that I paid for. I will sue Comcast/Xfinity if I have to because that's A LOT of money I lost. I need someone IN AMERICA to help me out and fix this. 

It is the WORST business decision to outsource like this and every company does it out of greed to save money when they already make plenty ripping off customers by overcharging. If I do not hear back from someone in America soon, I will begin legal action.