I NEED HELP!! Steam account not linking

I have added money to my gameflip account and I am trying to purchase an item for csgo. Whenever i attempt to connect my steam account it states that my login credentials are incorrect. My login is perfectly sound, it goes all the way to the point of saying sign in and i have to continue to attempt signing in with no success. I AM 100% certain my login is correct but this site is not allowing the connection of my steam account.

Hey, can you please send me your invite code via PM so I can check it for you?

Oh! Also send me a link to your Steam account so I can properly investigate this.