Outstanding Payment of invoices

I am a small business owner who was contracted to do maintenance work for FDC, it has been two months and my invoices haven't been paid. I received a call about a month ago from one of their financial officials stating that I can not be paid due to my tax non complaint status with SARS, that was untrue, I went to SARS to get proof which I even submitted at FDC and as a result they promised to pay my outstanding invoices. I have been running to FDC daily but to date I have not received payment all I get is lies from officials to management. I have employees that are dependent on my company and they are also inhibiting the growth of SnT Next Level Enterprise. I demand that I be paid my money, with interest for everyday that the money was late!