We've been a SFP seller since Sept last year, but on 1st Feb this year we noticed that Amazon changed the delivery promise date for SFP listings from one-day to two day.

Our Nationwide Prime shipping template is set up with automated shipping settings, and we use Royal Mail Tracked 24 and Tracked 48 as our shipping services with RM.

Now, with the exception of a few orders (only 12% in the last seven days were offered one-day delivery), Prime customers are being quoted two days for delivery on our SFP listings. When Amazon creates an order with a two-day delivery, it says it has used Royal Mail Tracked 24 as the shipping service used to calculate the delivery promise, so it seems that the delivery promise on Royal Mail Tracked 24 service is being padded from one day to two days.

There does not seem to be any sort of pattern to which addresses are offered one-day delivery and which are offered two-day delivery. A one-day delivery order was received from a customer based in Cornwall, while an order from a customer a few miles away from our warehouse had a two-day delivery, yet Amazon is using RM Tracked 24 as the shipping service to calculate the delivery promise on both orders.

Communicating with Seller Central about this has been pretty frustrating. The elusive Seller Fulfilled Prime team is not available on phone or chat, and the answers we receive when trying to gain some clarity on this issue are generic and copy/pasted, so having no luck there.

Is anyone else experiencing similar issues with their Royal Mail delivery promises?