Hi @aahidullah
Try taking some pictures using the camera and then download from the camera to a computer and check if they are OK.
I realize that you cannot see what you're taking but if the pictures are OK i.e. not black images, then there may be a problem with the camera's LCD screen.
If you determine that the LCD screen is faulty, here's the ifixit [guide|9789] guide that may help.
Search online for [https://www.google.com/search?client=firefox-b-d&q=Samsung+S730+lcd+screen+|Samsung S730 lcd screen] to find suppliers that suit you best. (examples only)