New india assureance
Mediclaim bill not setteled and new year cash less fax not replyed

My dad has medical insurence from 2001 of 100000 which he had been renueing till date he got dignosed for sugar and bp in 2002 in 2009 he got dignosed for rectum cancer of melignum mellonoma and got operated for the same and the bill shooted up to 2.5 lac of which at least the companie should have paid 1.3 lac but they simply paid 50000... later he got admited for heart problem and the hospital had cashless facility and the hos. guys sent fax to the companie didnt reply at all... new india and medi assist is no one cheat what should i do for claiming the money back