I bought a pair of shoes and the seller sent me a different size than what I bid on. I contact the seller and she told me to send them back for a refund. I plan on sending them back USPS priority mail with insurance and deliver confirmation. I also plan to get a receipt for postage - since it wasn't my mistake I believe she should have to pay for return postage. As it gets closer to the 45 days, if I don't have my refund then I'll open a Paypal claim. Is there anything else I need to do that I'm forgetting?