Refunding my money

Hi I purchased a cell phone on eBay on 22/08/2017. The phone refused to come on after i put it off. After much emailing the seller agreed on eBay to refund my money once I return the phone. I immedimmediately posted which cost me another 300 rand. The tracking on the phone states that the item is sitting at the post office in Ballwin USA from 16/10/2017 and seller has not fetched the item I contacted eBay yesterday asking for the status of my refund and now they saying they NOT going to refund my money. Even though I paid via PayPal. I have reported the matter to them. They have not responded to me yet. They asking me for police case number I don't understand why. Please I need help sorting out my issue. Also for some reason I àm unable to send emails to eBay as they I closed off the query. I am really stressed. Please help.