Whenever I send a buyer a second chance they have do make immediate payment to take up the offer. The problem is that shipping is added as well and in most cases the buyers have been sent multiple second chance offers. They would prefer combined shipping which I am happy to do. However if they have to make immediate payment then they end up paying shipping for each item and I have to go and refund through paypal. 

Is there a way to buy second chance offers but not pay until I do a final invoice? 

Thanks