One note: document everything brought up to HR. If it is a small HR department, they could very well be friends with the supervisor and take their side. HR does indeed exist to protect the company but it is also made up of people (often extroverted ones). Documenting everything can help you out if there is any sort of retaliation. A threat of a lawsuit is absolutely something that can make a company be very apologetic and much more generous. I have had several friends that made sure they documented everything and were given six months severance when there was a possibility of a lawsuit.