S4 Damaged goods after 2years of use

Samsung Team<br> <br> The best phone ever created by Samsung is of no value after 2 years of use. I am a Samsung fan and although I have a Samsung Galaxy Note 4, I still prefer the S4 more however its malfunctioning! It switched off on its own, gets hot, closes on its own while still using it I have tried updating the software there is still no change. Even planning on changing the battery but wondering if that will make any difference.<br> <br> Samsung please tell me what else I should do because I believe S4 is the best phone you'll ever created and I am not ready to part-ways with it. I want my life companion back but it is not functioning. HELP!