If they're not violating site rules, there's not really anything to report.
If you block them, it should stop you from being paired with them in a normal game. I don't know if that's implemented in 4-player, though.
To take a screenshot, hit the Print Screen key on your keyboard; that will copy the screenshot to the clipboard, and you can paste it into Paint or another image editor. Or you can install a screenshot tool such as Jing or Greenshot.
I have came across a LOT of cases where partners who: 1) disconnect 2) have bad sportsmanship 3) annoying eg. not listening.
Are there any ways that we can report them? Does the block member feature prevent us from playing each other AND being partners?
Thx Richard
[P.S. I don't have a screenshot feature thing going or just don't know how to do it on Windows 10 or chrome. If anyone knows, tell me please.]