Buyer stating she has not recieved item but then states their address was incorrect, now wants a refund?!

[beautiifulxsin]

I sold an item 2 months ago, and sent it to the members address stated on eBay. I am then emailed and told item not received as address is incorrect and eBay is refusing it change it. I was advised by post office it was sent to local post office of members suburb and it was received. Member has now told me i require to give a tracking number, which is has now been two months and i do not have the receipt. it was an expensive item i bought and sold and how member wants a refund. I believe it is not my fault as i send to the address on file assuming its correct !

What can i do in this case as i need to defend myself and i have never ever had any issues before!

Thanks!