What should I had done

You should have marked it as not received.

If you wanna go for those bonus points you should have also left a message on the giveaway and tell the creator the giftlink was already used. Then there are several options:

• The creator can give you a new one.
• You and the creator both agree to delete the giveaway.
• If the creator doesn't take any further action OR you don't agree to delete the giveaway just leave it "Not received".

Sidenote: If you mark a game as received which you actually didn't get people will assume you are a thief and probably sold the key somewhere or activated it on your main account.

That's what "Not Received" is for...

Should have marked the giveaway as not received.
That way the game was not missing on your profile.

And yes... always contact the giveaway creator if there is something wrong with the giveaway.

I see you left no comments on the giveaway at all, no thank you, but also no comment stating the problem.

When you get a game, that can't be activated you first contact a giveaway creator and inform them about your issue. They may want to replace the game, may ask you for permission to delete the giveaway, or may say "I don't care" (or just ignore you). If it's the latter, you wait for one week and mark giveaway as not received.

Did you marked it as received? Or you left it hanging - without marking as received or not received?

I get giveaway creators make mistakes. I'm upset the Mods didn't talk me and ask me what happen. The system won't let mark as "Not Received"

First of all .... read the rules.

"I was suspended for four weeks for not activating it"

If you don't activated only one win you get a 5 days suspension. You get only a longer one with more unactivated wins, in one or more cases.