Newgistics lost my AT&T phone return

I returned the two cell phones on my account back in October as part of my AT&T Next Upgrade Program.  My iPhone 6S Plus was processed, while my wife's phone that was remotely wiped, was returned to me at the beginning of November to have me wipe it again with her username and password. I did so and returned it in a small box with the packaging materials and the return label. I didn't think anything of it, and almost a month went by.  A letter with a charge for her cell phone came in the mail about a week ago. I thought it was a mistake since I used the label given to me to return the phone to the company that handles the cell phone returns, Gentech Technology Solutions. I checked the tracking on the USPS label on the website. It said it had handed the package off to its shipping partner, Newgistics.  I went to the Newgistics site and entered the tracking number. It showed up but said the ship date was unkown, the reference number was unkown, the destination was N/A and the staus was "In Transit." I called AT&T immediately and talked to a representative that tried to help me for over an hour with no results. I was transferred to customer loyalty and told that I had to research my own package and find out where it was and they wouldn't do anything to help me. There was no offer of a solution except to go to the Post Office and talk to them about it, which made no sense. The package was said to have been handed off to Newgistics on both sites.  I wasted 15 minutes talking to a supposed "customer loyalty" rep that was very unsympathetic and basically said I had to figure out my own solution and AT&T wasn't going to help me out.

I decided to contact Genco Technology Solutions to see if they had any idea where my package was since they printed the label and shipped the package and was forced to leave a message. I probably won't get a response from them.  So I decided to contact Newgistics and see if they could track the package.  Well it turns out they don't have any means to contact customer service. You can contact sales if you have the person's exact extension, but if you don't you get looped back to the main message giving you the exact same options. I have no idea what to do now. I am being charged for a phone that I don't have in my possession and have no way to find it since AT&T's trustworthy shipping company Newgistics is unreachable, and AT&T says it's up to me to figure this out when it wasn't even my shipping label.  I am baffled and at my wit's end. I know other people have had this happen, but I don't see a clear solution to this. Any advice on how to resolve this situation would be greatly appreciated.  I'm probably going to resort to posting on social media next.