no contact now through messenger and say that, as per their thingamabob on the primeamajigger, that you get a free month of prime and whatever shipping costs you incurred (if any)
edit: also, one time they marked a package as delivered 30 minutes after the specified time (in a different area), so I spoke with a CS rep and they said that they'd ship out another one and give me a free month of prime. Apparently It did arrive later that night (I'm assuming the delivery guy marked it early so they had time to drop it off whenever), but by the time I was able to talk to a CS rep again, they just said to keep it (the second shipment). that was neat