Trade in Warehouse gives erroneous reasons for pricing and completely FALSE

I called the trade in team today because I noticed my LG G6 which I checked before trading in was valued at $40 on the ATT trade in website.  

They received the phone and cut the value in half because the said there were "dead pixels"

I know what dead pixels are because I work in IT and I inspected this phone thoroughly and even ran screen tests.  There were zero issues.  

I asked for pictures or someone to talk to there to show me where this was on the screen and they said they cannot do anything of the sort.  

This trade in was directly tied to a $700 credit for a new iphone that I bought when I switched from Tmobile so I followed everything perfectly.  I plan on contacting the FCC and BBB as well because I know from experience that ATT does not care about their customers.  It took me two days just to activate my brand new phones as an example because they could not get the right person on the phone.