When I'm discussing with a person in regards to sending a phone away for repair I always suggest the following @klebsiella
Take time and date stamped pictures of the phone to prove its aesthetic condition.
And take one of it turned On to prove it powers up.
Unfortunately if your Samsung Support channel is saying there was no Bixby Button in the phone or packaging and won't budge on that decision then the next step would be to raise an official complaint via the online form on Samsungs official site and see if there willing to offer a gesture of goodwill.
Noone on the forum can circumvent an official response already from Samsung Support @klebsiella
Daily Driver > Samsung Galaxy s²³ Ultra 512Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "