Whether or not you were an indepent contractor or an employee is something that is very factually driven. Simply because you used their equipment and worked out of their office doesn't necessarily make you an employee. Whether you were an IC or an employee, you deserve to get paid for the work you did, however, and an attorney familiar with wage and hour law should be abel to help you. Not sure you'll be able to find one that'll take you on a contingency basis though.
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Need to know a few more facts, but if I had to guess, sounds like you may have been misclassified. Many employers misclassify employees as independent contractors. It's fairly common because the employer can save a lot of money in employment taxes, insurance and other benefits. Either way you are entitled to be paid your commissions. It's possible that I can help you.