I marked a site as spam and this error cause me to deleted the site users

Hello All!
So I was deleting spam users and spam sites, when making a bulk changes the site timeout to 504 Gateway Time-out

For some reason one of my sites go marked as spam and the users attached to that site got deleted. I unmarked the site from spam but when I try to add the missing user i get no luck but what is strange is that as shown in the following screenshot the users list said 2 users but the one missing user is not shown?

http://awesomescreenshot.com/0774p8wue6

I am sorry if this is not going to be an easy one!
Thanks in advance!
Waldemar