After taking lots of opinions from few Service Centers and other workshops, I went with the option of repairing ECM.
Kun Hyundai (@ Hafizpet,Hyderabad) sent it for repair to their outsourced facility in Faridabad, HR.
After 2 weeks I got the ECM repaired, but the Hyundai folks told that the ECM was damaged because of the Ignition coil and this also should be replaced.
So total expenditure was 15k :( which includes 7300 (ECM repair) + 5800 (Ignition col replace) + 290 (4 spark pugs) + labor charges.
Here are the pics of what they replaced with: