Arbitrary Reduction In Salary

I, a VRS retiree, was appointed by a central university on contract, initially for one year as a consultant on condition that my salary shall be paid as per a certain OM issued by the UGC. in the beginning, for one month, I was paid a salary as per the above condition but from the next month, it was reduced considerably without my consent and proper reason. I continued to work for two and a half years as they extended my contract period for the period until a new appointee joins. Later on, they terminated my period abruptly without any notice. Kindly let me know: Can I insist upon the university to pay me arrears as per the condition mentioned in my appointment letter. And, am I entitled to get salary in the lieu notice period.