Having been through this from both sides as seller and buyer; the shipping company will only deal with the shipper as he is the one who paid for the service and their contract is with him. As he accepted your money with the good faith promise to provide you with a pair of speakers in whatever condition(s) were described, it is his responsibility to make good on the sales contract. I suggest you contact him and either agree on some set additional time for the speaker to be found or inform him you want a full refund and that he provide you the means to return the delivered speaker. If you paid with paypal they can help. If not certainly contact the audiogon Admin as offered above.