Samsung S4 — Software complaint after upgrade to lollipop

Address:

Faridabad, Haryana

My phone (samsung S4) was working perfect since 2 years, but now my phone became worse after upgradation of lollipop software. Soon after upgradation it starts showing some problems like sudden power off and also becomes completely blank screen while using any of the applications and also i lost all my stuff which i saved in knox app. This happens 3-4 months back and i already informed the same through mail twice to samsung. And the reply which i got was not satisfactory. i am not in a stage to afford another mobile. do the needful