Main Events Marketing & Merchandising Did not pay me for a completed job! Albuquerque, New Mexico

Back in late September 2009 I was contacted by Linda Lopez.  She had gotten my name from Shadow Shopper and offered me a job as an independant contractor for Main Evens Marketing and Merchandising.  She said she was in a bind and needed someone to do a job right away at Sam's Club.  She emailed me information and I faxed her my I-9 and all other information that was asked for.  I did events at Sam's Club in College Station on 10/10/2009, 10/17 and 18 and again on 10/24/2009.  I did the job asked of me.  I stayed on my feet at Sams for 8 hours and handed out samples and information on each of the event dates.  I have only heard once from them that a check was to be mailed out on 11/13/2009 (this only after I refused to do an event on 11/72009).  I STILL HAVE YET TO BE PAID!  I have contacted them daily.  I have emailed and left voice messages.  Nothing.  They will not speak with me.  They will not return any emails.  What is left for me to do?  These people owe me $320 for the 4 events I did.  That is what they promised!  Help?!?!