HobbyKing (like a lot of places) are out of stock on lots of lines because of the factory’s being shut for a while and selling what they had.
Last week was my first time using HobbyKing (EU warehouse), but other Far East suppliers (Ali Express, BangGood, etc) are they are usually reliable, I have never had a problem but others have, PayPal is usually wise and watch the time limit on Ali to object.
Batteries are problematic now with the postal shipping rules (which make sense for safety) so I personally would be a bit cautious to order a LiPo or LifePo4 from outside the EU in case of problems.