coilcollector,
I understand it is disappointing but please do not post personal info (real name, address, phone number, email) publically. I removed them.
There are some things you can do. A negative feedback is one of them and making other buyers aware of the issue is another.
ebay can 'ding' the seller on cancelled transactions but it is unclear if this always happens or if a seller can negotiate their way out of this happening. And of course there is always the civil legal path that Chris has outlined. I am not a lawyer but there might also be something in the Uniform Commercial Code laws (state by state) which might cover 'binding transactions' if you think the ethical reasons are worth the battle.
I dislike that
ebay has this policy but 'binding transactions' are a sticky area for them (in both directions). At the end of the day
eBay's policies allow the cancelling of a transaction and we all agree to their policies when we sign up and use their services.
Don