Repeat Buyer Claiming Non Receipt + A-Z Claim - Amazon Buy Shipping Used

Hi guys

A buyer has claimed non receipt for two orders a month or so apart value £25. Sent using Amazon buy shipping RM Tracked 48.

First one shows the item photographed in the letter box, just before being pushed through. Second one shows a photo of the requested 'safe place' behind a bin with the correct door number painted on it.

They message to say not delivered, I reply with tracking, screenshots, say all the right things etc. A couple of days later the A-Z claim comes in which I lose because there is no signature on delivery. I have to fund the refund but I am protected from a defect as I used Amazon buy shipping.

Clearly this buyer knows what they're doing and is playing the A-Z card knowing full well they will get a refund. Surely Amazon would pick up on buyer behaviour using repeated A-Z claims for refunds?

I assume I can't claim anything from Royal Mail as it is delivered? No recourse from Amazon as that is their policy that the seller refunds if no signature. We are left open to this kind of scam unless a signature is taken on delivery which is not practical for this kind of product value.

What would you do in this situation? Thankfully, I've not had too many buyers like this over the years, but how could I give this buyer a 'shot across the bows' without upsetting Amazon!

All the best

Jay