Here's my take.
If you have a hold on your card, got an email and text yesterday saying you'll get your phone Friday, and this morning received the text saying "we're shipping phones today using overnight," then cool it.
-- even if you don't have a hold on your card, it takes literally half a second to charge a credit card.
Tracking information will come this afternoon and the phone will get here. UPS is prepared for this and will be working with T-Mobile all. day. long.
They're doing this piecemeal, which is the only way to process hundreds of thousands of orders... they just can't be processed all at once, and there is absolutely zero reason to stress yourselves into anxiety over this!