non-compete agreement

I was employed by a software consulting firm in Southfield, MI and was placed at client in RTP, NC. I had signed the non compete agreement. I worked at client thru my employer for over 5 year. Last year my employer found guilty of many charges and instead of appeared in court;left the country. The fedral court put the company in court recevership. During that time I went on vacatoin for 4 weeks after I came back my vacation was not paid to me and also the quartely bonus. At the same time client had made the decision to get the software contractor only thur the prefered vendor. I helped my empoyer to contest for it to become a preferred vendor for client but was not selected as a preferred vendor. At the end of year when contract was over. My employer did not gave any information about what will be the future for me, so I switched the consulting agency and joined the preferred vendor and worked at the same client and after two month client offered me a job that I took it. The preferred vendor has no problem me joining a client but now my old employer has sent me a notice that I am working at client and is violating a non compete agreement.

Please advice.