Hi @Alfie
As long as the seat characteristics are the same (ie not aisle) and the seats are next to one another the exact numbers you deliver does not really matter. For instance if you have seats 9-12 and sold 11,12 it is ok to deliver 9,10. Also for some reason when you sell Stubhub lists the range of your seats so in this example it might appear as though you sold seats 9 and 12.
If you go back to your listings what seats remain?