How do I obtain money owed to me by a company?

I have been working for a company doing ';work at home'; secretarial duties. Pay agreement was salary based paid once a month. I have been doing this for approx. 6 weeks and have yet to be paid. I have been trying to contact the ';manager'; via email and she is not responding. With that in mind, I began emailing her manager and still nothing in communication from either of them. I do not have a phone number for them only a fax number.