iPhone 13 Pro Max on Backorder

I ordered iphone 13 pro max 512gb silver on November 27th. After that I saw the estimated ship date between dec-13th and dec-20th. Now I see the shipping date changed to dec-21 to jan-3 . I have to travel on jan-1 and unable to receive the phone any later. Does anyone have information on iphone 13 Promax 512 gb silver.

I have seen different dates for different people. Is this consistent. What options do I have given it's already 1 month now

I got it under bogo offer and already received 1 phone , Sierra blue 256 gb.

Note - phone shows delivery by 28th Dec on apple website,  does this mean the phones are already in stock. AT&T and Verizon also say these are in stocks. Not sure why tmobile is taking so long. Really dissatisfied,  please let me know any ways to expedite the shipping