Hi Capacity EN-EL14a EN-EL14 Lithium Ion Battery for Nikon D3400 D5600

I purchased this as a secondary battery for my camera. Looking at 1800mah i was expecting to get atleast 600 photos as my nikon battery with 1200 mah gets me around 450 photos. To my surprise i am getting only around 400 photos and, I charged it to full and placed it in my camera bag for next days use, when i put it back in my camera i see that it already lost power has only 2 bars inspite of charging it to 100% pervious day. Worst part i paid extra to get in one day shipping.

It will not work in my Nikon D5600. It gives a message that says it can not communicate properly with the battery and will go no further. There is no bypassing the message. Seller said to bypass. So I checked the voltage on the battery and got 2 readings, one 8.2 and the other 8.3.. Don't know if that is the issue. In any case it won't work and I don't want to destroy a $600 camera with a $14 battery. I have the original battery and another generic, both function fine. Waiting on seller.