What can I legally do if I feel that someone forged my W4?

I have worked at this medical office for the past 8 months now and there are so many things that have happened. I am wondering if I need to take legal action. When I first started I was forced to volunteer for a week and a half to train for my position. Then when I started the normal new hire packet there was no W4 for me to fill out but taxes are still being taken out. I received a w2. Also I have been harassed by a coworker and even the so called manager has made comments about seeing us in bikinis. It's very uncomfortable.