Hyundai — Ecm damaged within 4 years of car- no after service assistance

I have been using hyundai for 10 years in different segments of cars. I purchased hyundai verna SX 1.6 petrol in 2011 . it has run for only 36500 Km . And has been regularly serviced at hyundai service station. This time i had a issue of engine light turning on, they checked it and repaired it, it wasnt rectified and now when i gave again for servicing they are saying that ECM is damaged needs to be changed and it cost 80000 rs. I request you to take this further - I demand a change of ECm or some revert on solution to the ECM problem.