Back to the old days of waiting for cheques to clear but even more time is required as banks don't seem to be under any obligation to hurry. They are happy to process transactions but the reversal can take quite a while. If the object was very valuable with an unknown buyer, I'd be upfront and tell the buyer I wasn't shipping for 14 days after the money was in my account. At least then odds are in my favour that I get to keep the money. If seller doesn't want to deal with that, they can buy from someone else.