Absolute Hyundai Ray Monks, refused to pay invoices for no reason Mesquite, Texas

I own a boutique advertising agency located in Dallas, TX. Absolute Hyundai hired me to plan their TV Advertising and Marketing. Even though I brought them more customers than they had seen in a long time, and all advertising was approved by Ray Monks (General Manager) before it was booked with the TV stations, Ray decided to stop paying my invoices. 

Because my invoices didn't paid in full, I can't cover the cost of all their TV commercials. TV stations are also trying to collect their past due. I've been told by a TV station that their accounting department contacted Ray Monks regarding collection and was told Absolute Hyundai paid the entire amount to me and I was supposed to pay the TV station, not Absolute Hyundai. He ran my name through the mud calling me a thief and a crook. 

A manager at the dealership confided in me that Ray Monks laughed at my collection efforts, saying "I don't need to pay her. She's a small shop and can't afford to take any action against me." 

I'm sure Absolute Hyundai has no intention of paying me, and is trying to get the TV stations to collect his past due balances from me instead of him.

If Absolute Hyundai really did send a check that got lost in the mail or something, it would be easy for their accounting department to produce a check stub, or cancel and reissue a check, but so far they haven't.

If you're currently doing any business with Absolute Hyundai, I would be very careful. This disaster has cost me much more than just the unpaid invoice amounts - working with Ray Monks has damaged my reputation, hurt my business, caused me to loose sleep, cost me medical bills, taken funds right out of my daughter's piano lesson and food off my table.