Hyundai Motor India — complete engine breakdown within 3 years - hyundai xcent

My hyundai xcent entire car engine got collapsed as per the service team of bajaj hyundai baharich up. My car suddenly stooped and got some noise from engine immediately got my car to authorized service center of hyundai and as per them it was a problem of self start and it was informed to me that it will take approx inr 18000. But next morning again when i visited the service center the technical team said that we have to open the entire engine because of some major fault and i was shocked to hear that because my car has not even completed three years and only touching 39000 km till date. And while buying the car it was promised that it has 2 +1 years of extended warranty but service center has totally denied for claim under warranty as per them it has only 2 years of warranty. Finally after lot of discussion my car engine was open after three days and the most shocking part was the repair estimate given by service center is 1, 40000 and company has denied to pay anything entire coast has to paid by car owner. Please can you suggest me what has to be done in this case.