Samsung Note 4 endless problems

I have got a Samsung Note 4 and my device just starts restarting on its own, when it restarts it does it for over 25 times and if u lucky it will stop, I have sent my phone to Samsung in the wedge shopping centre and they done software upgrade abt 3 times, also the attitude in that place is really poor. then eventually changed the board and it started to work, know after changing the board when I save my pictures from bbm or download a picture I can't view it on my gallery, I am having endless problems and I am really frustrated and looking for assistance from the big management from Samsung, pls contact me ASAP