If it's yours and you have purchase history from ur bank card you can easily get it back within 24 hours, at least it worked that way for me. Just contact support and that's it.
i sent them it they said its not enough but its wtv bro either way riot support is bad + i just made this alt and bought 2 skins from nightmarket for cheap which are good aswell
idk then, in my case i just answered their list of questions and sent last 4 numbers from my bank card with which i made purchases and got back my account immediately.
100$ is not that much for a game actually it is like a good amount of money like prob 3-4 days worth of food in asian countries but in terms of games not that much i spent 1k on apex lmfao
To be fair, I bought turkish accounts for the cheaper VP and the currency on my account changed like a month ago from TRY to GBP so they must keep tabs on it to some level