$45.00 is full payment for the price you paid for the brackets. You send them back to him, he refunds you full price of $45.00 you paid for the brackets.
I bought my wife a pair of jeans off ebay for Christmas. I paid the price of the jeans plus shipping. She didn't like the way they fit (not sure what I was thinking!). So, I did a refund request. I send back the jeans and when they get them, I get the cost of the the jeans refunded.
I pay for shipping both ways. That's the way its done, period.
