If post has to be signed for Royal Mail employees will verify delivery at the door and then record the code 'xD1' to indicate delivery. This arrangement was put in place so that customer contact handing a device to a customer to sign for an item themselves didn't bring staff and customers within two metres of each other. Names like 'Amy' are not legitimate proofs of delivery especially with the agreed 'xD1' in place and also on the grounds of [as you say] Max having the wrong tackle to even be considered an 'Amy' ... Don't bother with your local post office but get online and obtain the central customer service and complaints [08457] telephone number for a quicker result. This will enable a 'Lost Item' enquiry to be directed at your local Sorting Office Manager who will take the matter up and 1/ Check the Post Office Item GPS System for your parcel's location if it is still in the system. 2/ Have tracking number handy as you will need to give this to the service rep you speak to and for tracing purposes. 3/ Interview the Delivery Staff member who will be traced as to what was done with your parcel. 4/ Come back to you with their findings if they cannot enable immediate redelivery to you free of charge.
Source: This happened to me three weeks ago. Item now delivered safely.
Best of luck I DO hope you get this resolved 
