IHOP

I recently worked at the Ihop located on 2319 Lincoln hwy. Lancaster PA. I have recently left employment sat a local ihop due to constant bullying. The managers did not handle the situation even though this fellow employee has been confronted about her constant bullying. Instead of handling the situation or firing the employee who has been causing multiple problems in the restaurant they let me go who did nothing but step away from the issue so it didn't Escalade . I want to maybe ke a complaint. Who would I speak to to potentially get a investigation started for this ihop?