please tell me how to report an elo booster

Hey guys, met a good player in ranked. We added each other as friends so we could play another ranked game together. He told me that he would have to remove me from friends list after game because he is from Ukraine and he is boosting this account. I realize that most reports are made in the post-match screen (and I did report him for cheating there) but I also have screenshots of our conversation where he tells me that he is from Ukraine and he is boosting this account. Is the post game report enough? or should I make a ticket with links to the pictures of chat? If so, how do I do this?