My bathtub won't drain. I have removed the face plate on the overflow and there are no other parts visible! When I put the snake down it comes right back up the tub drain and vise versa. If the plunge is stuck, how can I remove that and can that be the trouble? When I bought the house, it was only the face plate and the lever is totally covered with calcium deposit and apparently was broken off prior. Please help! Thank you.