I've bought a wholesale lot off them a while ago, but I suspect their site isn't up to date because they emailed me about 12 hours after I placed the order to say one lot wasn't in stock.
The order arrived very quickly after that and in great condition. However, like many other drop shippers, this is probably just a case of back order problems.
Offer the buyer the option of a refund or replacement of the product with another item and put this down to experience.
We highly recommend contacting drop shippers once a week to check on supply levels to avoid this kind of thing happening.