There are a few buyers that do not follow through.

Usually I just try to contact a couple of times, then file an unpaid buyer with Ebay. Just state facts..buyer did not pay. If you want your seller fee returned for a non-sale you have to file. 

1. I do not get mad. I just file non paid report.

              2. Usually block bidder.

Here are links to do that:

Here is the report an unpaid item. You will need the item number. Normally..this is done in your transactions page..and there is a link.

http://rebulk.ebay.com/ws/eBayISAPI.dll?CreateDispute

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  It usually goes to add bidder to blocker bidder list..for you once you get FVF..

Here is the link for  block bidder list.

http://offer.ebay.com/ws/eBayISAPI.dll?BidderBlockLogin

Once I blocked the bidder..and then they contacted me and completed sale and wanted to buy something else.. They were in Hospital. Have come back and been a terrific repeat buyer.

I  deleted the auction when a buyer accidently bought two also. 

Remember, we all sometimes make mistakes. Getting mad won't get you anywhere..bad feedback makes you look bad to other buyers. The buyer can always leave feedback.

I have had sellers cancel sale for me when shipping was not as expected & they cancelled one when I bid on wrong toner.  [If a seller does that for YOU...cooperate with getting sellers fees recovered. I've even offered to Paypal the listing fee.].

That's what I do. Hope it helps.

Normally I do not leave feedback until it is left.