You have to be very careful with courier companies...
On most shipping waybills there will be a box that you will have to mark to indicate that NO SIGNATURE IS REQUIRED (NSR)...
Some drivers have been known to mark the NSR box on their own if you aren't there to receive the delivery ( a lot of companies pay the drivers a set amount per delivery). Others will drop to a neighbour and have them sign, although then they normally will leave a post-it note on your door.
If Fukuyama shipped the package and did NOT check the NSR option, the courier company is responsible for the cells. If, unfortunately, Fukuyama uses the NSR option as standard, they run the risk of billing disputes as there is no means of having a signed 'proof of delivery' from the customer.
This happens every day when working with couriers. The customers signature on the waybill indicates that the package was received with the packaging still intact. If there is no signature, there is no proof, therefore opening the door for a dispute
