my toilet keeps running and filling up with water and I keep dumping it out. It has leaked onto the floor and through the ceiling. black lid inside toilet broke off. How do I get the water to stop overflowing onto the floor?
You apparently have two issues.
A. The built-in trap of the toilet, or the drain line from the toilet, is clogged up or the excess water would simply be draining down the line without overflowing. Try a toilet auger to clear the trap. If that doesn't do it, you will have to pull the toilet and snake the line.
B. Replace the flapper ("black lid"). Cut the rubber ring off of the back of it and attach the two little "ears" onto the bracket hooks at the base of the overflow valve. (Works smoother that way.) Adjust the chain to where it just allows the flapper to fully seat and seal. (Excess chain length can get twisted and hang up and prevent the flapper from sealing properly.)