I'm sure a postman will confirm (there must be one on here) that if a parcel is sent non-registered/recorded then you cannot claim against the post office, it is down to the SENDER to replace the goods, it's not up to the purchaser to chase his items. That is why it's more expensive to send out the parcel recorded/tracked.
If the company has been stupid enough to send out an expensive item/items without proof of postage then that is their problem and they should either return the money to the purchaser or replace the goods, sending them out RECORDED next time
