Amazon.com, Inc Missing shipment - Amazon.com made claims that cannot be confirmed Seattle WA

To place my order with Amazon, I chose Prime shipping and the cheapest price of a business that had items in stock. Some companies said "Fulfilled by Amazon" but were back-ordered. This is the first company that was not back-ordered and it also was "Fulfilled by Amazon".

It was supposed to arrive today. It did not. I reported this to Customer Service and they told me to wait 2 more days. I could have ordered elsewhere and received it tomorrow !!!

I checked the tracking number on USPS. All it says was "On it way to USPS" and that it "departed a shipping partner" today (the day it was supposed to arrive!)  and "This does not indicate receipt by the USPS or the actual mailing date. "

Yesterday I signed up with USPS for text and email updates. I have not received any.

In other words, USPS probably does not even have it yet !!!

Yet Amazon has told me "the order was indeed shipped on time but got delayed from carrier's end".

Amazon claims the back-orders will be at their company on June 2. And the rep told me to wait until June 3 !!!

I do not believe them. There are currently 7 companies "Fulfilled by Amazon" and the first 6 (including mine) are now back-ordered. Since the company I chose is now back-ordered, as well as many other companies, I believe I have not been told the truth. I do not believe it has been shipped.

Is it fraud to sell items and receive payment for items that you do not have yet you have not told your customer that it has been shipped?