Pirated or Genuine DVD

Hi,

I need some advise please. I purchased the DVD Once Upon A Time from a seller in the US in August which I now have listed.

However, it's only just now upon closer examination that I'm questioning if this is a genuine copy.

I checked sellers feedback and some neg's say seller is selling fake copies, whilst others give positive feedback about quality etc, hence the reason I purchased it. I've also watched it once and it's good.

I've contacted the seller to question who his supplier is, but haven't received word back as yet.

Should I cancel the listing if this is questionable? I've searched google on how to spot a fake, but can't tell. 

Any advise as to what I should do as bids are etching higher and I don't want to disappoint the next potential buyer nor want the negative feedback.

Many thanks!