Hello 'atvender',
A couple questions, -- you do not say where you bought it, when, . . . or much else about it.
Was it a GSP item? That can make quite a difference.
If it was sent through the GSP, you can contact the seller and show him several pictures of the damage, but chances are he packed it really well but when the folks at the GSP warehouse opened and repackaged it, well, they don't give much attention to other people's items.
So you will want to then open a claim for 'Not as Described', say in the claim that it was a GSP item which was damaged by the shipper, and eventually you will get refunded without a return.
In a case like this the seller is considered not at fault (although it is considerate to apprise him of your situation) because the GSP center repacked it. They don't want a bunch of broken items, however, so when Pitney-Bowes breaks things they just refund.
You might end up having to call ebay (Help & Contact link at top of the page) and speak to a GSP specialist to get all your money back, but start by opening the claim.
This will still leave you with a broken guitar, but at least you will have all your money back (item price + shipping + import charges).
That said, if it was not a GSP item, you must first contact the seller with the photos of the damage. If it arrived as he packed it, it is considered his fault for not doing a better job of it. From here it will depend if the seller wants it back or not.
Sometimes on an unusable item they just refund, -- and silently vow to use superior packaging in future. If the instrument is simply, ah, 'inconvenienced', he may want it back and in Canada he can send you a Return Shipping Label.
If you bought from outside Canada, - even though the seller is still supposed to pay return shipping, the whole system is not set up for international labels. He could, of course, send you the money to your paypal account but ebay has no way to force him. You may again need to call ebay (Help & Contact) about it. But first see what the seller says. Assuming he is also a musician, he will fully understand the devastation you felt when you received a broken instrument.
Here is ebay's link about how to proceed with a problem.
http://pages.ebay.ca/help/buy/item-not-received.html#doesntmatch
I wish you well with it. 
