dissapearing skins

I rerolled 3 skins shards and got pool party fiora. when i tried to play it once i could not select it so i just ignored it. But recently i rerolled 3 more skin shards and got pool party fiora again and now it isnt in my skins, same as before. Riot support also could not help me because it was never recorded into their system. Was wondering if someone had experienced something like this or if it was a bug?