I just replaced the inside of the toilet items about 2 months ago. It was working fine until a couple of days ago my toilet continues to run and won't shut off. Lifting the back lid the arm connecting to the float is still down and the float is not raising with the water to shut off the water. I just take my finger and lift the arm to shut it off, but I wan't it to function properly like it did before. What could be my problem?