@syeedabanu this "Black screen but working and getting vibration" is a pretty good indication that you have a dialed display. I suggest that you replace the display.
Since ifixit does not yet have a specific guide for this, use something like [https://www.youtube.com/watch?v=Fr9jfcUG0eE|this video] Replacement screens are readily available at many online stores.
While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has a device with the same issues as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.
Repair is War on Entropy!