International Motor Productions Brigette Brown Cashed a check from Warranty Dept and $755.35 was to be mine and they say they never cashed check when I have proof Carrollton Texas

Long story short.....  I was in a wreck and car was a lose.  I had purchased a warranty on the car so the warranty dept sent Check to dealership. I called Brigette and she said yes the check was endorsed but never made it to her bank acct.  She said someone must have stole the check and cashed it cause it's not in her acct.  I had a legal office call to get a copy of the front and back of the check that the warranty dept. sent to her and she told the front desk girl at the legal firm that she was dumb, stupid, and probably worked in the cleaning dept. of the office and should not be on phone calls.  The lady was just calling to give a fax # to receive the info for the attorney.  What attorney calls on their own to do this????  Brigette then hung up on her without getting the fax number.  Brigette also told her that the $755.35 was piss money for her and if she had it she would give it to me since it is owed to me.  This is the rudest women in business I have ever had to deal with.  Not helpful and she has proof in her hand that the check was made to her company and cashed.  Not sure which bank it was cashed at but she has proof that is was cashed and still is denying it.  Stay far away from this company if possible.  I will keep fighting for my money that is owed to me but I have since bought a new car at a different dealership and the diffrence between how they run a business is night and day.  Brigette gives woman business owners a bad name.  She either has a chip on her shoulder, hates the world, or was just having a bad day and thinks she is above the law.  Either way I will not let her steal my money!!!!!!!!  BEWARE!!!!!!