someone cheating

I am starting to suspect something between x and y they are probably the same person while y first is created and the rating is boosted to around 2300 then he plays x who is the same person there games are too obvious such as 3 move mates can someone tell me how to report them? Thanks

Now they are playing blitz also x has only been playing y and that person has won all his games

here is the game archive ...

How do I report someone I think is cheating?

• If you have reason to believe someone is cheating, please report it here and include all relevant info (username, reason for suspicion, etc). We investigate all reports and keep them confidential. 
• Please do not discuss your suspicions in the forums!