If you've sent a cancellation request, don't hold your breath for them to accept it. You'll probably have to wait 10 days until you can close it yourself before you can relist the item.

Still screams scam. I'm not surprised you came back and said they couldn't pay. One has to wonder why they places 6 bids if they couldn't afford to pay for it. 

You could try contacting the underbidder and let them know what's happened. If they still want it, you can offer them a second chance listing once the cancellation has gone through.