Just was reading in another forum about buying fake Canon batteries from Amazon.
few lines for the other forum commnet
I was slightly suspicious when I found it to be a slightly tight fit when inserted in the camera, and did not spring out when the clip is released. The main giveaway is the serial number, genuine Canon LP-E6N batteries have an eight digit number, this one had seven.
Amazon were very good and gave me a refund and a potage label to return it.
Hope this helps