If it's a fake Cut it open and let's see the guts, if your really sure it's a fake what's it matter! My AQ coffee I bought from Best Buy, only because They gave me a huge CC one time looked just like the Diamond did in that unboxing video. Maybe the seller didn't know he had a fake! Either way he should've excepted a return, why risk a negative FB. I wouldn't bought it without him taking returns.
Also a fellow could swap out a real one for a fake and try to send it in, works both ways. I'm not implying you did that but I'm sure it's happened before somewhere like the turntable guy awhile back after 30 days he was scammed when the buyer said it was damaged.