Caution original is not always original

I got a "original battery" of any of the MarketPlace provider. He was just 5 time EUR cheaper
as Amazon itself. was delivered a battery in original Canon blister and apparently with original case (Canon imprint in the battery, the nameplate). The serial number is ever unreadable, the battery is significantly lighter than an original battery and is not recognized by the Canon EOS 7D.

It is a cheap copy, in original packaging. For me, it looks like intentional deception. So utmost caution for market place vendors (especially if they are new, no reviews have and send from abroad). If I now the battery (to Spain) send back I do not know if I ever get a replacement from the seller ....