If you still have problems after trying some of the suggestions, you could do what I did back in 2016. After multiple issues with Comcast, I wrote a 3 page complaint to the FCC. I was then contacted by the Comcast retention department. This guy got all of my problems taken care of. Ended up reimbursing me for my own $300 router, had the tech that came out run Ethernet cable through my house, then credited me maybe 2-3 months of service. They can do right by you, but they don't have to if you don't make enough noise about it.