What is the difference between a barcode and a no-answer code?

A barcode is a unique code (starting with '3S' or 'CD') which you receive as soon as the sender dispatches your parcel. Both the sender and the recipient can use this code to track the parcel online and see when the parcel will be/was delivered. The no-answer code is left by the delivery driver in the event that your parcel cannot be delivered on the first attempt. As the recipient, you can use this code to select when and where you wish to receive your parcel.