There is a Larin website:
https://larincorp.com/
Not really sure if they are a manufacturer or an importer. I know in the past there were Autozone Duralast jacks that were “made by Larin“. I’m unaware of any Larin rebuild kits.
If that main office isn’t of any help, this may be the case where you have to measure every seal individually and try to source them wherever you can find it. Yeah, that’ll be 30 minutes to take apart the jack, 3 hours to measure seals, and 3 days to find 50% of the seals, and 3 weeks to find the other 45% of the seals you need. The last few seals are probably some oddball size where you need to order a quantity of 1000 to get. How much effort you put into this is up to you, sometimes people consider jacks “disposable”, not because of the money cost, but rather the time cost. Sorry I’m cynical today. I Must be tired.
Good luck.