How long are rerolls taking this days?

If they have given you a key and do not wish to reroll, then you probably should accept and mark as received if it works. Leaving the key unrevealed and marking it as not received might mean you are in the wrong by SG rules or could lead to them actually making a ticket.

https://www.steamgifts.com/stats/community/support
in case you're curious.. scroll to the bottom.

I think so ;)

Received or not received doesnt technically have anything to do with if the key is sent or not. It has more to do if you have activated the game on your account or not.

In this case he asked for reroll. It has gone over 7 days and if the key isnt revelead then marking it not received should be perfectly fine if there is no respons from the creator.

madsession's comment is basically the tl;dr version of this one, so this one is more for those still confused and wanting a bit more elaboration on the matter.

But why would he mark it as Not Received if the creator did send the key?

In this case, that would entail "Not Received by Winner", rather than the usual "Not Provided Properly by GA Creator"

If the English on the site's terminology is confusing, try reading it as "Didn't Receive" rather than "Not Received". The label can as easily mean "didn't accept" as it can mean "wasn't given", as with "I didn't receive it when it was offered, I just left it there on the counter" or "I didn't receive it, I'm still waiting on it to arrive".

Again, it's considered impolite to jump to marking Not Received in situations where you're still communicating with the GA creator and have a reasonable chance of getting things resolved [a major example of this would be if you've won a prerelease giveaway; It'd be very impolite to mark Not Received prior to the game actually being released, or within the immediate timeframe duration of that release].

Beyond that, as I noted in the above post, the key factor here would be whether the winner revealed the key or not- if they did, and it's a working key, then the winner can no longer mark Not Received and, instead, is required to mark Received. After all, at that point, they have both been given AND accepted a working key, regardless of whether they activated it or not- hence, no longer qualifying for any of the three elements [provision, acceptance, functionality] which would allow for them being able to mark Not Received.

As far as affecting the creator, it would not, given that:

1. Not Receiveds are evaluated on an individual basis, and are only considered an issue if the GA creator displays a pattern of them.
2. The GA creator can still reroll/delete at any time, thanks to the comment/support ticket put in by the winner of the giveaway in question. At that point, the Not Received would be removed.

Of course, there are a few circumstances were there would be issue:

1. Marking Not Received without indicating that it's because of your own refusal of the giveway. This would lock up the GA for the GA creator until they can get clarification on the circumstances or validate that you're not communicating with them on the matter. It would also potentially create problems for the GA creator if it adds to a preexisting trend of Not Receiveds for that GA creator.
   
   On the other side of that, if the winner displays a trend of marking Not Receiveds in that manner, there's grounds to believe that staff would eventually suspend the winner. In fact, "Misuse of Giveaway Feedback" yields a so-called "Permanent Suspension", so it's entirely possible that you'd go from getting warning to getting a temporary suspension to getting an indefinite suspension by the third instance of staff noting such behaviors. Of course, that all depends on the staff members involved- some may be far more.. or less.. lenient on it. By the suspension premise, they could justify hitting you with a "Permanent Suspension" from the very first instance of such behavior.
   
   So, again: You do have the right to mark Not Received under premise of [non]acceptance, but you will want to make sure to clarify that that's what you're doing, when you choose to do it. Rather, making attempts to communicate clearly rather reliably yields positive results from both staff and other site members here on SG.
   
   Edit: After some more awake retrospecting: Actually, now that we have the <Reveal Key> function, the above paragraphs may no longer be true, since staff should theoretically be able to determine the lack of reveal and figure out the situation based off that. Probably still not a great idea to fail to communicate, but by this point even this "would be an issue" likely no longer would be such (though, as always, you should confirm such a thing with staff before engaging in the behavior), for any party involved, meaning that perhaps the only actual remaining concern would be the point just below
2. Having already revealed the key [and then marking Not Received] would directly put you in line for Misuse of Giveaway Feedback if you don't clarify that you didn't use it and get the GA creator's permission not to use it. That's a pretty quick way to screw over your SG account, so best practice is to take your time considering your win (specifically, your desire to claim it) before revealing a key or accepting a Steam Gift.

In any case, you have the right to refuse an unrevealed/unredeemed win. You're never* obligated to activate the game on your account and mark it as received (at least, not prior to accepting the win), nor to perpetually keep the giveaway active after you've already refused it. That said, you'll want to keep the GA creator's circumstances in mind, and communicate clearly. Failure to do either of those will give the impression of being a rather unpleasent individual to other community members [ie, potentially soliciting blacklists for yourself] and, as noted above, can even potentially lead to suspensions.

* Note, for example, how problematic it would be if you won a game you'd already acquired from elsewhere (but hadn't yet synced to SG, or wasn't able to filter out via sync due to it being a DLC or bugged).

On the other side of that, you're effectively signing off on the win when you reveal a key. At that point you've already confirmed that you want it and intend to put it on your account. As I noted, you could still potentially arrange something with the GA creator but, all the same, you've already thrown away your inherent right of refusal. In that instance, you could no longer justify a Not Received and would in fact be caught between the two options you just presented: That of leaving the giveaway active until the GA creator responds, or of activating the key.

Of course, if the GA creator responds that they expect you to redeem the key, then you'd want to do so promptly, as staff would then consider it as a Non-Activation on your part (and, going off past experiences, staff'd then forcefully mark the giveaway as Received, subsequent to the GA creator putting in a Request Received Feedback ticket- meaning you'd be getting a suspension for the Non-Activation while still ending up with the same end result as far as the Feedback).

Cat, 1 Cat 2, and Cat 3 (I'm not really good with naming things)