Apple trade in Screwup

So I get am email from Apple today telling me that my iPhone 12 pro max is only worth $30 on trade-in down from the original 790 I am mediately declined and told them to send me back my phone. After calling Apple to see why they were only giving me $30 on pretty much a brand new phone they told me it’s because I sent them an iPhone 6 mind you I did not I sent them the iPhone 12 pro max I explained this to them but it’s pretty much a he said she said situation I have remove the device from find my phone so I don’t have it registered in iCloud but I do have the original box with the serial number so now I fear the phone that they are sending me back is an iPhone 6 that is not mine and I’m going to be out $790 Worth of trade a Equity and I won’t even have my original iPhone 12+ max So I’m kind of double screwed