In reality you have no idea if the buyer is actually in China. They could very well be a registered Chinese buyer but in fact living in the US. They could however also be using a freight forwarder and be living in China but you didn't post details so no idea which situation you are in.
If you do not ship internationally or limit your international shipments to certain countries you can cancel the order based on problem with the buyers address. Some will argue that this is not a valid reason to cancel but it's your merchandise and your risk.
Ironically it is one of the ways buyers in the Russian Federation have found as a work around to the sanctions. They simply open a CC account with a Chinese bank and utilize a Chinese based FF to receive the items and then simply forward it to the buyer in the Russian Federation.
EBay proclaims that the buyer looses their money back protection when they utilize a FF but they have waffled on this at times and that policy is useless in the face of a CC chargeback. There have been multiple posts on this forum about buyers who bought high dollar high end items, cell phones and electronics being their favorite targets, and then once they had the items filed a NAD chargeback with their CC company. In most cases, based on the CC company decision, they were fully refunded and allowed to keep the item.
