iPhone Xs Max- received empty box!

Received an empty box from fedex yesterday. All that was included was the receipt and activation paperwork, along with a label to return my current phone (AT&T Next). The box didn’t look tampered with at all, the fedex label said “2 lbs.” on it (clearly was way lighter). After spending 45 min on the phone with an AT&T rep, I received a case number and a promise that I would be contacted within 4 days. This is after she tried to sell me on more services and another upgraded device because “have you heard? The new iPhones came out today.” Really? I had no idea.

Has anyone else had a similar issue? What am I supposed to do at this point? Wouldn’t it be better customer service to simply ship me a new phone, and then figure out what happened to the other one on your own time? Feeling very disappointed not in the fact that I don’t have the new phone, but just in how this is being handled.