Sellers are expected to deliver the item as described. If the item is lost or damaged when the Buyer receives it, the Buyer should contact the Seller and shipping company immediately. Furthermore, the Buyer must fully cooperate with the Seller in facilitating the claim process. The Seller should offer a refund to the buyer after filing a claim and/or receiving the returned item (in the event of damage), and then pursue a claim with the shipping company for reimbursement.
At the same time, Buyers are not allowed to request a refund if the item is as described. Whether the item fits the Buyer's needs or system is not relevant - only that it looks and works as advertised.
If the two parties can not come to a solution, or if one party is not willing to cooperate, then either party may consider filing a Dispute. Audiogon provides an online mechanism for resolving these problems: Submit a Transaction Dispute.