I've sent a support ticket about this type of problem before. Back when I was very poor I had horrible Wifi and we didn't live in the best place, so power went out a lot, I got flagged as "leaver" by the leavebuster system. This is just my opinion, but I don't think it's right to punish someone who is already at rock bottom because their parents are poor. The account I was playing on got a permanent ban off of a game where I came back and solo carried. I was in bronze at the time, so yeah this is a really long time ago. I came back and carried the game ( I went 20/0 or something crazy), and to my surprise, there was a, "you have been banned" notification. I sent a ticket and explained my situation. They told me they wouldn't do anything and I shouldn't rage quit so often. They told me I shouldn't rage quit. I was very confused because I heard that riot knew the difference between dcing and leaving, but this guy tells me that I shouldn't have rage quit. Support ticket probably won't help. They do no research on your actual problem. They look at the basics and nothing more. You left, you deserve the punishment is their motto. I'm in a better place and I don't dc anymore because of trash wifi. It's weird how I'm not banned from rage quitting on this account. It's almost like I was never a rage quiter in the first place.
TL;DR: Riot isn't going to help you. You could blame their lack of wanting to do research on your behalf or you can blame it on the kids that complain constantly about losing because of AFKs. Doesn't matter, you're not getting the LP back. Or at least that's my prediction.