Today I downloaded the game and surprisingly I still had my 70lvl account even tho I havent played before on FDO, but when I try to make some changes on my classes everything resets when I exit the game.

Either broken stats or extra .iwd's do you have iw_00-24.iwd?

No, I dont have iw_00-24.iwd

Then it's a stats issue.

"wtf?"

Ok... make sure that you have on your MW2 a folder named "players" (you should have since it seems that your stats were imported from there). Now make sure that you have permission to write on that folder (that it's not a "read-only" folder).

In order to save your setting, the game needs to be able to write on "config_mp", inside "players" folder.

The folder is read-only and I cant change it, it just doesnt save when I remove the check.

I made a new account and it worked for a second, but when I imported stats from EAM it got bugged again...

I made a new account and it worked for a second, but when I imported stats from EAM it got bugged again...

Don't try to import EAM then? You might be using some bugged stat files