If you shipped those speakers back to the vendor you bought them from in just the original packaging without the overpack they shipped them in they probably wouldn't except them. If for some reason you threw overpack away, Fed Ex usually can provide an overpack of some sort if they have it on hand at additional cost which in addition to insurance ensures your shipment gets to it's destination in one piece.
I make this standard practice when I ship to vendors say when they give me credit to trade up to a better-quality component. It's your responsibility and part of the deal!

