I NEED A GOOD ADVICE

I play this game from 2011 and i get a lot of fun. I need an advice a good one i get my 5 years account permanetly suspended for no reason at all. They say i use malicious 3rd programs or modification to my League of Legends game . I dont use any of these and i sent a ticket to their support team and they sent me back same mesage like i use this thing i dont know even what they say i use ... i do not do any modification or instaled any programs i just play ! After 1 day when i make a report of a player who instant kill me with 2000 hp with just R (with diana ) and he haved just zonya, boots and luden ecko...so imp[osible to deal such dmg... and after thjis report i dint play lika almost a day and i have and ugly suprise when i whas tryng to sign in game to play . My account its old enough and i have almost all champs just 6 more need to have them all, almost 130 skins like i have 4 ore more legendary skins i put almost 500 $ in game or maybe more...i get an PBE account after 1 year after i requested , before the tribunal get some modification i whas in the tribunal so i helped league of legends system for escaping the bad players ...i do not do anything wrong and i get this account STEALED by this ugly mistake of them .... i did not get after my second request of proove (cause they can't have none beacause i don't do anything) any answer. I just want Justice to be done i heared from a friend like my account worth can go to almost 1000 lire . I NEED A GOOD ADVICE ! Cause im will contact every one in staff of league of legends system to get my justice and get my account back.
I'm on Nord East Europe server and i will Ask every one to help me get my justice cause the person from my country League of Legends support staff dont give me any proof of that they accuzed me (cause they dont have one cause i don't do anything ) and still i cant use my account! Wish u all best !