I'm having a problem with my door latch not staying snug. It seems to have worked itself away from the black knob and doesn't "move" with the knob to turn it to latch. If I try and tighten the two together, it gets so tight that it won't move the latch -- if I try the other direction, it loosens itself up to where it doesn't hold the latch enough to move it. Not sure whether I'm describing this well, but nothing I've tried seems to work. Any suggestions?