That's not evidence of cheating. Maybe they've only played a few live games and their rating never had a chance to reflect their ability.
Maybe the person knows it looks fishy, but really is bad at live chess, and being made uncomfortable by your question when he has no reasonable sounding excuse, he blocked you. Maybe others have abused him in his message box saying similar things (even though you started out nicely).
Anyway, you can fill out a ticket to report abuse like cheating.
Some one plays extremely fishy.. he is rated 1300 in blitz/bullet, 1400 in standard, with online rating of 2100, his tactic rating is also 1300, with over 300 puzzles done.
His online stats : 65/3/1... very fishy for a guy with over 500 Blitz/Bullet/Standard games who plays very poorly.
I mention it to him it is weird, and he replied he cant think in games 30 minutes or less, but proceeds to block me? I never even accused him, so even more fishy.
Where is the report button? Thanks!