Dashcam on tailgate keeps falling off... Help! Any ideas?

The new Next base  dash cams have done away with the suction cup and now use an adhesive pad , I had the old Next base like yours with the suction cap that kept falling off, Now I have the latest one with the adhesive pad and so far (touch wood!!) its stayed put - no problem at all, 

Give Next base a call I am sure they will drop a couple of pads in the post. Also make sure the glass is dry and clean before fixing

All the best