[stephen low]

Think the auction house is in deep water as they are legally obliged to have correct documentation to avoid losing their licence. They obviously need to be sure they aren't trading stolen goods, so if numbers don't match they haven't done their job and you have a good reason to return the goods and get a refund, if that's your wish.

Else as Michael says, get the correct documentation having had them clear this first is their responsibility. You have the leverage in this situation.