xfinity not responding ??

for about 2 weeks I get pop up messages when trying to do anything on the internet and email. Called Comcast 2 times and they were no help . They said they reset something but the problem is still there. I see also all kinds of the  same problem being reported on the internet . Basically the sam problem I have. Also the internet is much slower and get some pop up messages saying it is too busy try later. This is very anoying . Do I need to switch my service ?????