In the tournament one of the players resigned winning positions on purpose to lower his rating. I chose not to play with {Mod} again. I ask him why but he only asked me why I didn't spell my words right. Do you think i am overreacting?

[Mod Note: No naming and shaming.  Send us a ticket instead: http://support.chess.com/Tickets/Submit]

eh, I don't think so. It is cheating (at least in my mind) to do so before a tournament, so that you can enter a more lowly ranked class and win easily. I too, would not play again against a person like that, but I don't think there's much you can do about it. 

you did the right thing.  Most players on this site are good sports, but when you go against a cheater, you block them so you dont have to play them anymore.  You can also report them to chess.com and they will look into whether they are serial cheaters and possibly ban them.

The weird thing is he won't admit but only is getting rude. But I feel the pleasure of playing chess with all the Nice others.

I believe it's a strict rule on this site that when you accuse another member of cheating, you must not name them!

The moderators watch out for that kind of thing.  Of course if you feel that strongly, report it....

http://support.chess.com/Tickets/Submit

...And another thing - before actually going through the steps of accusing, feeling bitter and reporting - do yourself a favor and check the game with a good engine... surprises are aplenty!

Speaking from experience, as the last guy I reported as a 'cheater' was nothing but me acting sour grapes on having lost in a really bad way. I never heard from chess.com about it, and on examination, the guy was pure as snow, blundering like the best of them (and of course Mr. Solskytz blundered worse and got his tuches handed to him)

Of course I did some research in advance.

@OP: stephen_33 is correct about naming and shaming. Alleged abusers should not be accused publicly.

The practice of resigning games for the purpose of lowering one's rating is called "sandbagging," and it is considered cheating on Chess.com. If you believe anyone is engaging in sandbagging, you should report the individual directly to Chess.com staff at the link given in stephen_33's post.

Since this topic is about cheating, all discussion on this topic should be discontinued at this point. Any wishing to continue the discussion should take it to the Cheating Forum, here:

http://www.chess.com/groups/home/cheating-forum

Oops... now noticing that I was commenting on the wrong thread. I was referring to computer cheating so that one plays better than he deserves... you are speaking about losing intentionally, which is much easier to figure out... so sure - report, ban, quarter and draw

i have found that not accepting the queens gambit is very hard to combat against. can someone help me with my queen gambit decline as balck problem

Could you please post the game (or final position at least)? It is possible - generally speaking -  a player misjudges the position. It has happened to me many times.