error #4 please look at this post

[vee333f]

so i have been having the error i have activate it on there website it said i have already activated it a i have tried contacting customer support they said that i had to activate it on my steam profile i tried it and it said invalided key the same key worked on there website so i replayed saying that it didn't work then they said to explain it better what more is there to say?  i have tried making a new account didn't work tried reinstalling it didn't work i no i spelled correctly since i login to there website with that account it worked just fine i triple check to see if i spelled it right what do i do please if you have any idea what to do please replay thanks