Trade in damage

So I would like to trade my iPhone 8plus for an apple gift card

it does power up, it charges, takes pictures speaker works etc. HOWEVER, it will not connect to WiFi, and it will not connect to cellular when there is a SIM inserted. No cracks on the front of the phone, but there is a 1cm crack on the back bottom left corner of the phone. It has not spiderwebbed or anything like that.

my question is, is when I am answering the trade in questions, they ask this:

Answer yes if all of the following apply:

• It’s free of major cracks, chips, and scratches
• If there’s glass on the back, it’s not shattered
• 

I would think since it’s not a “major crack, imo “ that I could check “yes all apply”

if If they do give me the gift card, when they get my phone, can they come back and say that it’s not worth that much later and, take away my credit?