Who I have the same questioned this topic

I just had something similar. I was given $275 for my iPhone 7+, but then got an email that because of an "unresponsive or cracked screen" it was lowered to only $138! It did not have either of these. I called, but of course they were no help. I guess Verizon gets to just adjust your agreed-upon price to whatever they please once the phone is in their hands. I would avoid this program completely, less you give up your phone and they have the power to do whatever they want. I tried to get the phone back, but of course they "can't do that". Naturally.