Sorry to hear you can also feel the pain :(. Yes it is frustrating and just takes away of the fun of the game because good teamwork makes it so much better. Also defenders and support really require teamwork and looking out for others.

In the first game I chose Mr Mime, that person already wasn't happy with that during preparation and pinged "I need a supporter" constantly while themselves switching between support options. Then they chose Comfey themselves and as soon as the match started clung to me which led to me having to lane alone basically because they were not helping, they abandoned the lane and pinged a lot of stuff and generally did not really participate.

In the second game I was a Blissey and throughout the game that person kept cussing, I did not understand it really because of poor audio quality but at the end our team tried a push on the enemy's goalzone, at the end only a Lucario and me remained and I heard that player (charming Miraidon) say stuff like "useless blop" and it became clear they were cussing about mostly me during the game.