Comcast is an ISP and Cable Television provider, with a terrible reputation. When I cancelled my service when them I had to mail the modem back to them. I did it UPS shipping with tracking, because I know not to trust them. They never-the-less claimed they did not receive it, and billed me for the device. Eventually - armed with the shipping confirmation - they acknowledged receipt of the package, but insisted that the box was empty and that I mailed them an empty box.

I forget the other details, but remember to never do business with Comcast or their subsidiaries / partners.

A few years ago, someone recorded a phone call with a Comcast retention rep who kept trying to tell someone to not cancel their service; it took nearly 20 minutes for someone to cancel their service:

https://arstechnica.com/information-technology/2014/07/call-...

Oof. I upgraded my wife’s business from Comcast to AT&T. This is the only context, ever, where you’ll hear me describe AT&T as an upgrade to anything. I returned Comcast’s modem to the local office, photographed them accepting it from me, and archived the receipt and photos for safekeeping. I do not routinely do that sort of thing with other vendors.

That sounds eerily like my experience 8 months ago with 'Verizon 5g Home Internet'. Lied to by the used-car salesman: "we'll give you $100 in credits", and when I canceled (mostly due to customer service saying "I see your $100 of credits, they are pending approval", then a few weeks later "credits? there are no credits showing on your account"), got nothing but runaround and a claim that my returned modem was damaged. I AM doing business with a Verizon MVNO (Visible, just because they provide the best deal for me, and don't really even HAVE customer service), but I will NEVER directly do business with Verizon again.

(Sorry; off-topic, but I needed to rant)