Demotion as Constructive Discharge — unpaid internship at for-profit company

I'm dealing with a situation and need some guidance.

unpaid internship at for-profit company. I've been dealing with this for about 4 months now and the situation isn't improving.

I have worked at this company for 4 years. My position is non-exempt and I do have a written employment agreement beyond the standard offer letter.

Has anyone been through something similar? What worked for you?

Not a lawyer, but I have direct experience with this.

I ended up having everything documented, which cost about $3-6 but saved me a lot more in the long run.