Ebay rules say a seller is not allowed to force positive feedback!
this is feedback extortion! report to ebay and he will never be allowed to sell again!
How can you leave positive feedback if you don't have your money??
file a claim with paypal not ebay
item not as described and give them the pictures and the tracking info for your return
when the item is delivered your money will be returned to you from paypal! it will be out of his hands
Do this before you ship back to him!
even if he is being fair this is just good common sense!