My champs are disappearing!

I wanted to try out volibear when he was free, and I really liked him so I bought him. I played him in ranked a lot, so that's how I know I definitely owned him. One day I wanted to buy a skin for volibear and apparently I didn't own him, even though I played numerous games with him in ranked, and we all know that you can't play free champs that you don't own in ranked. Another time this happened, but with a skin. Me and my cousin were mystery gifting each other and I got surprise party Amumu, I used the skin a couple times. Then one day I was playing with my cousins and I decided to go amumu to show off my skin, and apparently I never got the skin, even though I used the skin before. (This was all before hextech crafting)