Device trade in nightmare

I got the Google pixel 10 pro xl on release day and was told I had to send my Google pixel 9 pro xl in for a trade. I never received a shipping label. I contacted Xfinity multiple times and was told I didn't have to trade it in.

Last Thursday I got an email saying I will be charged the remaining device payments of $508 because I never shipped the phone back. I talked to an agent Saturday and went into an Xfinity store Sunday and both times were promised I would receive a shipping label and still never received it.

I'm not paying these device payments because I have no way of shipping this device back and I've tried multiple times to do this.

I also sent a different phone in for trade in on a different line and USPS confirmed the device was delivered on September 5th but I still don't have the $550 in device credits for that phone either.

So I'm being charged over $1,000 for something out of my control that Xfinity is not even attempting to fix.