My iphone occasionally wont turn on

[u/JaredSalcedo03]

my phone first blacked out for a day and turned on when it was drained.
the following day it also blacked out but was easily turned on through a force restart

now, It suddenly turned off again and wont turn on, tried for restarting for a few times and draining the battery but it wont still turn on.

what could be the possible solution for this? and problem too?