Is there a way to check the chat log history within in-game?

I'm really sorry to hear you had to deal with a toxic player and go through all that. 

If you reported them in-game you can rest assured that the report went to our Terms of Service Team which will take the appropriate actions. We’ll investigate it and take action according to our policies. For privacy reasons, we can’t give you information about our investigation or what actions we take on another player’s account.

In case you would like to know more about the ways you can report a player, please see: Report players for cheating, abuse, or harassment