Step 1. Flush a few more times to clean as well as you can. 2. Turn off the water to the toilet. 3. Flush again, now remove all the water that's left from the tank and the bowl. 4. Use a small compact mirror and a flashlight to look up inside the toilet for and thing that is not suppose to be there. Be patient, it takes a little practice. 5. If nothing is obstructing the bowl going up, then you will need to take the toilet loose from the floor, lean it forward very carefully, and look up the bottom side of the toilet bowl with the flashlight for and foreign objects. Hopefully it is that simple for you and can retrieve whatever it is easily. It will only cost you the price of a wax ring, about 5 dollars, to reset the toilet.