Cancel TV service and fix internet speed

I noticed I was paying about $60 more a month for my internet than previously. I never changed my plan, and found somehow I'm getting 800mbps internet and paying for TV channels I never signed up for. I tried to remove the TV channels and it tells me I'm in a contract which I haven't re-signed up for in years. I cannot get this removed through the chat feature and I cannot get through the phone system. How can I get the TV channels removed and my internet returned to the 150 mbps that I wanted to pay for originally. I never requested these changes to my account, and I've wasted a lot of money. Not happy at all :/