Contract workers who are subject to hostile environments can use resignation letter to terminate the agreement.
{Your address}
{City, State, Zip}
{Date}
{Recipient}
{Address}
{City, State, Zip}
Dear {Name},
As a contract worker, I understand that I am not officially an employee of {company}. Still, I am subject to much of the same treatment as the "real" employees, including {details}. As such, I have come to realize that I am not interested in putting up with it any longer.
My contract states that I may end this arrangement at any time, without any sort of notice period. Therefore, this letter will serve as the official notification of the termination of my contract.
Sincerely,
{Name}