Hyundai Motor India — hyundai service related issue

Address:

Frontier Matiala Hyundai Service Center, New Delhi, Delhi, 110075

I had given my car for overheating issue at frontier hyundai matiala service center new delhi.
Based on initial investigation they told me they will first change the radiator if that will not help they may need to check the engine:
1. The radiator was changed and they assessed the condition based on which they told the heating problem still present and engine needs to be checked. Estimate given based on this was around rs 8000/-
2. Then the engine was checked, they did the investigation and updated me that the pistons are overheated due to which piston rings and block needs to be done. The revised estimate was increased by rs 10000/-
The photographs shared with me were not right as the portion was not cleaned before taking any measurements and giving estimate. I visited the workshop and they acknowledged the mistake. They shared with me exact measurements based on which they told the phase is out and it needs to be corrected and the revised estimate was now between rs 30000/- and rs 35000/-.
I confirmed with them if there is any other issue which they foresee in engine but i was assured that this will fix the problem.
Now again i received call from hyundai service center saying the crank in engine has a cut due to which i may be hearing knocking noise during gear shift change. If it is left without replacement which would cost additional
Rs 12000/- then i would hear knocking during gear change. The car when given at service center had no knocking issue, now i am loosing confidence on the issue diagnosis and has two issues:-
I. I do not have budget to pay for this continuously increasing car engine service. Why without proper diagnosis the estimates are given and i am pushed to pay for that.
Ii. I am not sure if my car engine actually had these many issues.

I need correct fix for the issue with proper diagnosis and correct estimate. Also i should have an option to opt out from the fix as i may not have capability to pay them due to incorrect estimates given by the service advisors.