We have been working for this company as a contrac...

We have been working for this company as a contractor for 4 months now. We are currently past due on payment for over 2000.00 dollars. We have to continually call and are constantly being told that the payment is processed and a check is in the mail. They constant try to go against the contract and not pay. I currently have done 10,000.00 dollars worth of work and as soon as they get the bill they are trying to tell me they sent out the contract wrong and they are not going to pay all the invoices. I have signed contracts and all the data where we have provided the correct services as per their contract. They are very disorganized and not able to keep up with the billing cycles. They constant change how they want information sent and do it with out communicating to the vendors. We have jumped through all the hoopes with them for months only to not get paid.