I have had loads of problems with those cams. You will probably find one of 2 things.
1:- The batten may have snapped just where it enters the cam. Remove the batten and you will soon see. The small bit that remais is a right bitch to remove so good luck if that is the case.
2:- Where the batten enters the cam may have widened. It should be a slot but the plastic seems to be a bit weak and may have stretched to an oval shape causing the problem you describe.
Good luck with it. They are a great sail when they work. I just hope Tush can sort these cam problems. Probably not even their fault. Factories are well known for not using the materials specified by the manufacturer at times.