I totally understand your frustration here. Losing an A-to-z appeal when you've used Buy Shipping and provided the carrier name can feel really unfair, especially when the only issue is that Royal Mail didn't scan the untracked package.

Here's what's happening: When you appeal an A-to-z claim, Amazon's investigation team looks for proof of delivery, which typically includes tracking information showing carrier scans. For delivery-related claims, they need details like the dispatch method, proof of delivery from the carrier including the tracking number, and carrier details. The challenge with untracked Royal Mail services is that without scans, there's no tracking information visible on the carrier's website—even though you provided the carrier name correctly.

When you use Buy Shipping, you should receive certain protections. Buy Shipping is designed to help protect your Order Defect Rate when you ship on time and provide valid tracking. However, the key word here is "valid tracking"—which typically means tracking that shows carrier scans.

If you want to continue using untracked shipping methods for lower-value items, you might need to factor in the risk that A-to-z claims could impact your ODR if the package isn't scanned. Alternatively, you could consider using tracked shipping for all orders to ensure you have the delivery confirmation needed to successfully appeal claims.

For this specific order, I'd suggest reaching out to Selling Partner Support and referencing that you used Buy Shipping and shipped on time. You can also mention the order details and explain that Royal Mail's lack of scanning shouldn't penalize you when you followed all the proper procedures.