Valve doesn’t have a great system in place to deal with a group of griefers especially if it’s a pre-made 4 man. It ruins hours of your life having to deal with people out to just ruin your game and there is not a lot you can do about it. My last game had a team of 4 griefers, in the end, though they all got banned half way for too many team kills or to much team damage.
With a pre-made team of two, you are unable to kick either of them as they won’t kick each other even if one is trolling or ruining the game for the other three players. I’ve always found the best course of action is to just report the griefer or both of them if it’s both and ignore them. Most of the time if you just completely ignore them they get bored really easy and start focusing on the game since you’re not entertaining them.
If they’re abusing you remember that valve does have a mute feature. Muting them will not only block their voice chat but also text chat. If you want everyone muted you can always use to developer console command “voice_scale 0” which turns the in-game voice volume down to 0.
Unfortunately for a 4 man team, you can’t do much as a lot of them in the lower rank will just kick you for no reason at the end or near the end of a game. The good news is if they do this to enough people within a certain amount of time they will all get a 7-day competitive ban for kicking too many people. It isn’t uncommon and I see a lot of people complaining about it on the CSGO Forum and on a related subreddit community.
You could use the advice above which is the same as the two-man team and mute them all. They will tend to get bored as well but that won’t stop them from kicking you. The only way to prevent that is to be queued with a friend or be lucky and hope that they’re only a three man and the random won’t kick you. Most people who realize that there is a pre-made 3 man won’t kick you if their trolling or griefing because they know they’ll be kicked directly after.
The worst people are those that try and get you banned by standing in front of you. You can’t do much about it except rush towards the enemy to keep ahead of them. If you hold back or let them stick with you they may try to block you in a corner so you can’t move. Once again it’s best to ignore these players and just try and have fun doing a tactic you most likely don’t often do, rushing. It might be worth trying out weapons you don’t use often to get a good feel for them as you rush in so you get some practice.
Team flashers aren’t as bad as most people make out. They will only be limited to 2 flashes unless you stay in your spawn because you can buy additional flashes after you throw one if the buy timer hasn’t run out. Not only do they have limited flashes but they need to throw them in front of you to be effective, and we all know griefers do not have much skill. Don’t give a reaction back to the griefer, just dodge the flashes if you can and they’ll most likely move on to someone else not long after or once again get bored.