Facebook and USP

Hi all. Today I wanted to get USP so I ask friends how to do it. They told me, that I must click "I like it" on facebook at crossfire account. Then I found tutorial how to get it and... I learned that I must do it via crossfire page... When I did it, I could see "U already got weapon" or something like that.
How can I fix it and have USP ? I, of course, didn't get this USP...
Please answer me, thanks.

Greetings