FedEx Saturday Delivery Unavailable - Buy Shipping Services no longer allowing services that are available elsewhere

We've been able to ship 2-day orders with Ship by Thursday and due Saturday with FedEx no problem for a long time.

3 weeks ago, Amazon no longer allows you to buy FedEx 2-day with Saturday delivery (for orders that are due Saturday). Can't buy it manually through Buy Shipping Services, can't buy other programmatic ways either. It's just not an option anymore. I'm specifically buying "Express 2-day One Rate Saturday" service in most cases but there are no FedEx 2-day Services with Saturday shown by Amazon.

My FedEx account is connected through Amazon and I can still buy through my FedEx account without issue.

The issue is Amazon.

We've had to stop certain offerings altogether and update certain postage buying away from Amazon Buy Shipping because available services are no longer available through Amazon.

It's been a major pain for a lot of reasons including that we're no longer protected from claims/delivery issues since we're not Buying through Amazon in many cases. Plus it's just a huge hassle to have to split purchasing between Buy Shipping and our internal solution. Amazon do you have a fix for this?