I've never heard of them so did some looking up.
Your package is stuck, I thought in Louisiana until you said Customs, but stuck in LA usually means they shipped from Asia.
They do not have any storefront or brick-and-mortar presence, but their HQ is in Delaware, maybe for tax purposes. They sound like a website-only business who is just a dealer, that is not a problem for me, there are vendors who do the same. Squadron and Scale Hobbyists are two of my main vendors and they do not have a shop as in ye' olde hobby store. Sprue Brothers do, but most of their business is mail order. Just saying that being an online only store is fine with me, but not if orders are sent to me from overseas sellers, that just means you're a middle-man.
I have recently sworn off on purchasing anything from overseas, Australia/New Zealand and Japan being exceptions. The long delays and expense are bad enough, but now I am getting unexpected bills from FedEx and DHS for tariffs. A $5-10 charge is not a deal killer, it is the $20-30 tacked on charges for "servicing fees" that made me to decide I only order domestic (with few exceptions) for now.
Please avoid any politics about tariffs, I do not want to go there. But as long as there's no free trade with Europe and much of Asia I'm no longer wanting anything shipped from there. Just my opinion but, Hobbyist Haven should ship to US customers from their Delaware warehouse like the tier-1 vendors I listed above do, even if it was made in Ukraine or wherever.