RIOT Remove The leavebuster effect

I Was in a server for a few minutes, then** my computer crashed** so i had to restart. After i restart i joined back the game(The game was half way through finishing), and i played the game all the way to the end. After the match ended i got a message saying that i was afk or something like that then i had to wait for 20 minutes, so could you cancel my leave buster. (P.S This was not the first time)