Incompetent techs - no accountability or compensation from xfinity

I've been an Xfinity customer for years, but till now, didn't have any issues with their customer service. Long story short - at the end of February, my internet starts dropping every day and won't come on without restarting the router. I called Xfinity tech, and they arrived and checked everything - they said the connection is fine, and the only reason the internet is dropping is that my modem is old and doesn't support 2.5GB speed.

Ok, I changed the modem for the latest generation of Netgear; it has greater reviews and is easy to install; it's compatible with Xfinity and is one of their approved modems. The Internet seems to work ok in April and May, but the exact same issue returns in June - the internet keeps dropping and will not restart without a complete restart of the modem. At this point, I'm having guests staying at my place who work from home, and reliable internet is an absolute must. 

I try all the possible troubleshooting suggested by Xfinity and the maker of the modem it doesn't help. I made an appointment with an Xfinity technician again; they come, check everything on June 22, and change the coax cable, and again the tech tells me the same old story -  the issue must be my modem - the one that isn't even 6 months old. Ok, I decided to order the modem from Xfinity directly to eliminate this issue. 

Internet disappeared completely on June 24 -  the modem shows as "offline" in my Xfinity app; absolutely nothing helps. Thinking that modem is the issue, my guests purchase the brand new modem the same day ( the one from Xfinity is still somewhere in the route) - a different brand, good reviews, and we're trying to connect it to have internet back. 

Surprise - I can't activate my new modem via Xfinity app because their system doesn't see it (tho all the cables are secure). I spent over 2 hours chatting with their tech support people, and finally, I'm told that the modem wasn't the issue, but the line is. The line that supposedly was checked by their own techs TWICE in the last 5 months is the root of the problem, and not my modems, as I was told before. 

 Of course, the tech isn't available over the weekend; there's no internet at all. 

The earliest appointment is June 26 in the afternoon, and Xfinity pledges to send "a senior" person. Luckily the tech arrived and explains that there was no signal coming from the line at all, thus, the modem wasn't receiving anything - the tech changed the line that runs outside the house. After they have done it, the connection appears!  He promises that there will be no more issues with the drops as well  - as if now the internet is running smooth, hopefully, it stays the same way.

Xfinity apologizes for the inconvenience but doesn't offer me any reimbursements or even some sort of credit. I had to reimburse a substantial amount from my guests due to this whole Xfinity debacle that only happened because two Xfinity techs were completely incompetent, wasted my time, and didn't fix the real issue when I first flagged it.
I had to spend hours trying to troubleshoot my equipment when the real problem was their line, and I had to waste a ton of money and time purchasing new modems, trying to install them, and bringing them back. 

As a customer paying over $100 per month for this service, this is unacceptable for me.