The 3pt frame is loose from the deck of the rotary cutter.
The lift arm adjustment threads are stripped out, you are turning it, but it's not raising or lowering the lift arm.
One other thing to check, the bracket up by the seat, it could be stripped out, when you raise the lift, be sure that both arms are raising together. They are connected to a large shaft that is located behind and under the seat. If one of the lift arms is stripped out these two arms will not lift equally.
Just raise and lower the lift a number of times watching one item at a time and you will finally determine what is causing your problem.