eBay

I sold and item that was not described correctly and I decided to refund the client. I have been trying to find out how can I buy a return label from ebay to be sent to the buyer? Also since I already refund the money how can I obligate the buyer to ...

I sold an item which weight end up being a lot heavier that what I expected. If is the buyer who pays for the shipping but the amount is less what should I do?. I know eBay will make the adjustment from the profit and then I won't have any money left...