Rika, as i said many time so far, i have provided many many things other than KYC to verify myself as original sender and everything.
Well, they claim that you haven't provided them the the proper proof (order page etc) that you are the person who ordered those miners. Since you are just a newbie account with no history here and they seem like a legit business, I am leaning towards their side of the story.
They should receive negative feedback to realize that they cannot run from that.
You failed to provide the evidence that you have been scammed, as simple as that. Hell, I wouldn't be surprised if you don't end up with negative feedback since they created scam accusation topic against you.