Cant link Steam account and Garrysmod

Recently did some retarded link your account with steam in order to use the damn site. BUT MY FECKING LOGIN AINT GODDAMN WORKING.

its like what the hell. Im not getting it wrong and its constantly telling me my login is incorrect. but I use these details to login to steam. Its going from frustrating to enraging. help please?

Did u buy Gmod legally ?

im pretty sure you just log in with your Steam Login details now.

Username: “Steam Name”
Password: “Steam Password”

Thats how i have to log in now