Brought a laptop battery off the bay which came with a 1 year warranty, after about 4 months the battery broke so I got in contact with the guy who said send it back and we'll deal with it. The guy has 10,000+ positive feedback so I was confident that he would deal with the situation. I sent out the item via signed for international delivery (to Hong Kong) on the 9th March and hes saying he still hasnt received it. Ive checked on the Royal Mail website which says it was delivered on the 13th. Ive told this to the guy and showed him a copy of the receipt and now hes not responding to my emails. Anything I can do?