Company asked to serve notice period as per new norms and conditi

Sir my bame is vinjamuri ravikanth . I want to know the solution for the below mentioned status of mine . I joined a company and i am working with this company for past 6 months . As everything was verbally discussed regarding my salary an incentives and past more than 5 months i am not getting my salary on time and past 6 months my incentives are on hold and now even my salary is on hold past more than 2 and a half months . So rit now i applied for a notice period for 30 days but i didnt received any offer letter or an appoint ment letter and company is asking me to sign an agreement forcefully if i leav the company i personally have to hire a candidate of my caliber in my replacement And also giving me some unachievable target to get my salary and dues cleared and if i will not accept it they will not release my salary and incentives as well as my resignation so as i am financial facing a lot of problem so i did signed it . So what to do next i dont know please help me out . Because hen we discussed verbally no such contract was ever there it cane up when i asked for the resignation