Billed for unreturned equipment

Billed for equipment that was returned was assured it would be removed but then every month since January i have been billed $15 was assured it would be removed was never removed so I said until it's fixed I'm not paying the equipment was returned and I still kept getting billed. I finally get someone who says if I start making small payments they will remove the equipment charges the charges were still not removed but I made a payment on the 13th and had it set to pay the rest of my bill with my upcoming paycheck then 2 days later on the 15th of July you cancel my internet and add an additional unreturned equipment fee of $150 so now you have my bill at $445 and I only had access the the internet 1 week for the past 3 months but still kept getting billed for that as well. I've been with xfinity for 7 years now and never had a problem until the end of last year and all this year. Never had charges that were not mine or unfair but now all of a sudden everyone is having this problem. I'm not sure if you guys are just trying to scam people or what but I think I'm just going to seek legal advice and take legal action because I've been trying to get my bill fixed since January and no one I spoke to of the many many employees helped or honored their word or doing anything to fix it.