I believe I also had a bad experience with JCLPCB just now and my current recommendation is
AVOID JLC PCB.
In my situation, I had a terrible experience when using their Parts Library. I did place an order and realized 3 minutes later, literally, that the order has been placed was incorrect.
I recognize that it was MY MISTAKE and I contact them asking to cancel the order and charge me any transaction fee it might occur, but they refused and I lost USD800.00.
We all know that the parts library, once you order a part is just a "Digital Transaction" that only reserves the stock for your use. By the way, the part was not externally sourced (the part is actually from LCSC). Basically, nothing got physically changed, touched or shipped. Also, the part had a large stock and I didn't prevent any other customer to place other orders for the same component. Literally, zero loss for JLC PCB apart from a few entries on their system.
Unfortunately, they insist that once the parts are in my Library they can't issue a refund, cancel or even ship the items to me so I could think about what to do with the parts later.
Well, I'm not a big company but I spend about $7K-$15K on PCB, parts, prototypes and PCBA per month. Not sure about you all, but if my customer makes a mistake and there's zero cost to me, or even if there's a small transaction cost, I happily revert the transaction... it's just professional cordiality that we expect and get from everybody else.
And now, because of a bad policy (or the fact JLCPCB is being greedy), I will put them at the bottom of my list when choosing someone to manufacture my designs and stick with more mature suppliers.
ps.: Maybe JLC PCB can see this and comment
Update 10/May/2022: After multiple attempts to contact JLC PCB I raised a dispute via Paypal. This seems to be the only way to have them re-considering things as Paypal can be reasonable sometimes when ruling disputes. After that they allowed me to book a DHL courier (using my DHL account) to pick-up the parts and those were delivered today. I haven't unwrapped it yet but the parts seems to be all there and properly packaged.