Here is a completely different approach: Completely without any pressure on the cell phone. It is simply inserted from the top, where it comes to rest between the side fences. Since it is so wonderfully sheltered, and can not possibly get out again. And so it also can not run away upwards, the upper limit is there. And that is not as flexible and snaps, but it is a separate part that is connected to the mobile phone holder by a hinge and a spring. So it works automatically downwards away when the phone is inserted and then springs back up according to where it blocks the "escape" upwards.
So the phone is in its limits and may at any time (upper limit flap folded away and remove) are very easily removed.
It could not not go, even safer.
One more note: Ex works the upper limit is designed so that you can postpone the phone even from the bottom upwards, without first pressing the lid backwards. This can suppress but by the top two "support arms" fixed around bends around the top edge of the phone with an engaged mobile. In this way, the so crooked that you can slide out nothing also from below, but must press the flap for removal. So that everyone can adapt according to his needs.