Normally, eBay treats 'not as described' as a 'he said/she said' situation and requires the buyer to return the item on his own dime (or dollar) with tracking.
First, contact the seller. Try to come to some reasonable compromise.
Will the seller accept that the error in description is his, and pay the return shipping?
Is it possible for you to sell the item locally for less of a loss than the cost of return shipping?
If the seller is in Canada, can he send a prepaid return shipping label?
Things that eBay suggests that don't work cross-border.
The US (or worse overseas) seller CANNOT send you a return shipping label.
The freight company will not usually refund their customs brokerage fee.
The seller never saw a dime of that brokerage fee and eBay does not require him to refund money he never saw.
You can get your Canadian customs and sales taxes back from CBSA, when you return the item to the seller. The information is on the back of the invoice you got from the shipping company.
In addition, the most effective feedback is calm and factual. You have a full 60 days to leave fb, don't be hasty. Nasty fb will kill any chance of a reasonable resolution.
When you leave feedback, you will also be asked to leave Detailed Seller Ratings. A normal transaction gets 5 Stars. Anything lower has a strong negative effect on the seller's ability to list and sell.
