Contax 645 Black and White

Well I bought an used Contax 645 medium format camera on ebay.  Great camera, loved it.  But it had to go back because of lines on the images and too much dust in the camera.  But Im not giving up, I will find another one (a little cleaner) to buy.  No flash.  In the dark.  3200 speed black and white film.   Eighth grade graduation banquet.