If you paid for the postage, then you can't claim it back.
For future reference, if you are returning an item which is faulty or not as described, and the seller has to pay for the label, you need to contact Ebay if the label supplied doesn't cover the cost of return.
Then, usually, they will issue you with a label and charge the seller.
If you pay yourself, you won't get a refund. Sorry.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)