he was just better than you, get over it
cheating-i suspect software was used

Computers don't lose to people like you. If your position was resignable by move 20 then maybe you could say something, but you won. Like #2 says get over it.

If you sincerely think someone is a cheater, submit a ticket.
http://support.chess.com/Tickets/Submit
in a tournament.....a guy was surely using a software........i mean he had 14 min out of 15 min left in 15/10 game n i had 1 min left at the end of the game.....though i won.....he was making correct moves accurately......n i dnt think a human can do that.......plus his blitz rating is very low may b coz he cant use software in less time......he could beat a player who is too good........too good ...........200 points high....with time.......HOW TO REPORT