It appears the most reliable sequence is through the 877#.
"Backordered" goes to "Processed" goes to Shipped. That's how it was for me. None of the online order statuses changed until it shipped.
Though on the processed, you will only get that status by calling the 877 number or 611.
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For those keeping score, it took approximately 3 hours for ATT to email me a shipment notification after it said shipped on the 877#.
I didn't get the shipping notification for almost 8 hours, so times may vary.