It sounds like you signed based on additional terms stated verbally at the time of signing. To win you will have to prove what "she" said and that you complied with the terms she stated. Get the lady's name and position. To get the $500 back you will need to file a small claims suit. Before filing I would demand they honor the verbal agreement or face litigation.
-Michael R. Juarez Law Office of Juarez and Schaeffer PO Box 16216 San Diego, CA 92105 (619) 804-4327 www.jslaw.org Mike@jslaw.org This posting is provided for “information purposes” only and should not be relied upon as "legal advice." Nothing transmitted from this posting constitutes the establishment of an attorney-client relationship. Applicability of the legal principles discussed here may differ substantially in individual situations or in different jurisdictions.