Centerboard Stuck
How or why the CB is stuck depends. Most likely, there is growth in the sleeve that hold the CB or something has gotten forced into the slot. If your boat is out of the water you should be able to figure out what to do. If your boat is in the water the only real choice are to get the boat out of the water or dive. If your in a marina with ski boat type lifts you may can borrow one or else your going to have to pay to have the boat hauled. Mine got stuck once after running aground in mud.Are you sure your CB rope is not stuck?