answer:If this happened to me, and I was genuinely interested in returning the items cost-free, my first step would be to phone the merchant and explain to the manager what had happened. They will very likely arrange for them to be picked up from your house, which will cost you only the inconvenience of being there to greet the shipper. The only risk in this scenario is if something happens to the shipment during the return. I would be tempted to contact the poor sod whose invoice you have, so he doesn’t wait several weeks for an expensive item that he’s already paid for and doesn’t know is not in transit to him. Not because I’d send it directly to him (that’s a bad idea), but so he knows that this is happening. The merchant probably won’t inform him.