What you are saying is that the seller send an item that is Not As Described.
Did you open a Dispute within 30 days of receipt?
If you did, and returned the item, you would have won the Dispute and got a refund.
This would also remove your feedback.
Think of it as 'double jeopardy' . You can leave an opinion of the transaction or you can get the refund, but not both.
If you did not return the item, you would lose the Dispute. Again, no feedback can be given.
If you did not open a Dispute and the 30 days have passed, you can go to Paypal instead.
PP Disputes are available for 180 days after payment, but you must return the unwanted item on your own dime.
I don't think PP disputes affect eBay feedback, but I am willing to be corrected on that.