remove mophie pack from iphone 6s+

for the first time ever following this explanation worked:

When removing the case be sure to never grasp the sides as this will prevent you from removing your phone. Remove the cap from the juice pack. Place the case in the palm of your left hand with your thumb and pinky "cradling" the case (do not grip simply rest them there to make sure the case doesn't fall out of your hand). With your forefinger and ring finger grip the top of the case (just under your phone). With the palm of your right hand place it on the screen of your phone and with a firm, but gentle pressure push up and out of the case. As if you are rolling a clay snake.
Alternatively, grasp the bottom of the juice pack with the palm of your left hand and the top of your phone with your right palm. With an even force pull your phone straight out of the case. Do this in the same manner you would unplug an extension cord.