please, i bought a lumia 535 phone a couple of days back. The phone's screen just all of a sudden started showing blank (black screen). i still get notifications, calls and messages can still coming but i jst cant see any sort of display. What shld i do?

my ppa, a priv sec schl in lagos island gave me a rejection letter.told my platoon inspector about it and she said i shld go look fr a private firm because it will take ages fr nysc to re-post me. please any form of help will be greatly appreciated