Paddle collision

[codebeginnerg]

I have a problem with my code where the ball doesn't accurately detect the collision of the paddle on all point it deflect the ball at a certain area, but not all. Here is the paddle dimensions from paddle class:
x= 550
y= 170
width = 15;
height = 90;

 class ball
          {
        int x = 35; // initial x position of the ball
        int y = 190; // initial y position of the ball
        int dx = 20; // position increment for the ball on the x axis
        int dy = 20; // position increment for the ball on the y axis
        int xBall = 40;// width of the ball on the x axis
        int yBall = 40;// width of the ball on the y axis
        court c = new court();
        paddle p = new paddle();
        public ball()
        {
        }

       public void drawBall(Graphics b)
        {
            b.FillEllipse(Brushes.Green, x, y, xBall, yBall);
        }
       public void MoveBall()
       {
           int newBall_x = x + dx;
           int newBall_y = y + dy;
 
           // Bounce the ball if it has collided with a wall
           if ((newBall_x < 30) || (newBall_x > 570)) dx = -dx;
           if ((newBall_y < 50) || (newBall_y > 320)) dy = -dy;
 

           // Bounce the ball if it has collided with the paddle
            if (((newBall_x + xBall > p.paddle_x) && (newBall_x + xBall < (p.paddle_x + 

         p.paddle_width))) && ((newBall_y + yBall > p.paddle_y) && (newBall_y + yBall < (p.paddle_y + 
         p.paddle_height))))
           {
               dx = -dx;
           }
           x = x + dx;
           y = y + dy;
          

       }
    }