I purchased Lee Sin a week ago, and played him a few times. Today I tried to play him again, and he was not selectable, and now I see he is not in my collection, I didn't do anything, and I have no idea why he isn't owned by me anymore.
You should probably send in a support ticket to see if they can help you out on that.
If you are certain that you purchased him, but want to double-check anyway, go to your purchase history in "store" and confirm. But him being unselectable could mean he is banned from being picked (by ur team or enemy)
If none of the above, yeah I suggest you send a ticket.
Best of luck
