the problem between seller and his own supplier is not customer's concern. As far as customer knows, they have paid the money and expect goods to arrive. It is seller's own responsibilities to fork out his own money to refund customers first. When you do business, you must have set your own money aside for cases like this. In business world, this is called liquidation.

If you do not have the ability to do this then don't start a business. If it is that easy to run a business then any tom, d*** and harry can be millionaire.