Champions disappearing

So i have played League of Legends since 2013-2014 and between 2016-2018 i almost didn’t play at all.

I remember that i had every champ in the game except 7 champs or so, and When i starter playing again in the besinning of 2019 i noticed that a LOT of my Champions were gone, for exemple - Kallista, Renekton, Ahri, Diana, Elise Ekko, Kallista, Quinn, Nautilus and so on.

And i remember clearly that i used to play there champs often, and i now that they weren’t free to play as i played them often and over long periods of time.

So i sent in a report to riot, but since they can’t see it in my shop history they can’t prove that i’ve had them.... So what shall i do and have anyone else experienced this??