so you recommended me that i use input pullup?
Not it you are already using external pulldown resistors.
Get rid of all the code that is performed when a switch is pressed. Verify that you can detect each and every switch press correctly.
Then, add code back in. But, you must be aware, as MorganS mentioned, that your code will NOT be very responsive to the switch presses, since it is NOT reading the switches during the delay()s.