My client is going to hire my employees as they are working onsite at client comapny...

Hello i had been providing professional engineering services and support services. as we are provide well engineers to claient for them support services as they dont have time to do the training andall so we are doin that work. as we had been deployed 3 employee on site. according to them we had been train then and provide fullfill them requirment and providing services. as currently they had not going further with our services as they had not work for the 6 yrs.. now they are dirctly contact to my emplyee and divert them for the work through another contract. as i had been defined terms and condition for the client at time of estimation regrding you will not be hire our employee directly or indirectly....and also for the emplyee that they will not join any client company directly or indirectly. as manager had plan to bypass me because of this they had not renew my contract and they are directly approaching my employees,,,,as they are doing bad politics in works... i had been already request to client management all HR Manager and leagel team regards this matter... how can we go for the law... thanks