Winner isn't responding. Do I have a right to re-roll?

Hello everyone.
I need an advice.

5 days ago user won my giveaway. I emailed him the key, which is still not activated, according to this user's game list.

In these days I was sending him a few e-mails in case he didn't receive the first one. Also I tried to add him in steam, but still no response even if he's online.

I'll wait for 2 days more and then.. what should I do?

Can I re-roll after week is out if key is still not activated?

And what if he marks as "not received" though I tried to contact him multiple times?

Thanks in advance.

Thanks everyone, he responded and got the key.