Why when i unlock something, and i quit the game, i start the game again, and the things that i unlocked are no longer unlocked? Can somebody help me ?

Did you unlock the spinning skull symbol?

nope, happens with every account i have, everything i unlock either its a weapon attachment or perks, just dissapears after i log back into the game

Delete all of the .stat files in your players folder, delete iw4m.ini, make a new account snd log into it.