Cleaner shrimp dont actually eat ick. But they will go a lonfg ways towrads keeping your fish happy and comfortable. The will consume detritus, slime, maybe some small ectoparasites, but they do not consume ick cysts. Linda, the fish are surely using the cleaners, just not in your view. My fish are the same way. Once I come near the tank, they insist its feeding time, and nothing else matters.
However, I do agree with Cameron that, although certainly not a cure, they will help a lot in general fish health. Just keep an eye out for a significant infestation. There may be a point where you'll want to treat.