Umm so is this mystery gift coming...
Not sure if it just takes time because of the minority or what but the mystery gifts are taking some time since i already own riot
and your supposed to receive a mystery gift if you already on it. 
Not sure if it just takes time because of the minority or what but the mystery gifts are taking some time since i already own riot
and your supposed to receive a mystery gift if you already on it. 
i suspect...
....they are probably doing some combo of manual SQL queries and alphabetical order.
do the maths.
On one account, I temporarily lost my Kayle and the Skin for a short period of time, only to find everything was back two logins later.
wait till the 23rd m8. then send a ticket in. I havent gotten my mystery skin either so they are probably trying to figure out a way to disperse them correctly so the people who already owned her are the only ones getting a mystery skin.