4-FA has been extinct for a long time now. I can get 4-FMA , albeit much more expensive than what I used to see it for ... $70 for a single g now VS. the $20-30 i was able to get it for around 2015. My guy also had 2-FMA there for a while earlier in the year..but has since run out and unable to restock. It was the same situation on the price though.
I have seen 1 or 2 shops recently with 3-FA , but they don't ship to the U.S. That's the only one I don't think I've ever tried.
I miss 4-FA and 2-FA , and 2-FMA is good stuff too just not as recreational. But 4 and 2 were amazing. Good luck on finding 4- , it's probably been close to 10 years since I've had any personally.