Decline or accept upon receipt of damaged gear

I'd appreciate the forum's opinion...

I recently purchased a used amplifier from an online seller.  Payment was sent and the amplifier was shipped via common carrier.  Upon arrival, the package and amplifier inside was visibly damaged.  An inspection through the holes in the damaged box found no packing materials.  After taking photographs, was it more appropriate to decline or to accept the shipment before working with the seller for resolution?