Daikin Air Conditioners / Daikinindia.com — i have been facing trouble with the unit from the day it has been installed

I have been provided a defective unit of the daikin 1.5 ton split inverter ac that i purchased from reliance digital sector 29, gurgaon. I have been facing trouble with the unit from the day it has been installed.
1. 5-jan-20: the air conditioner was installed by the reliance digital service team. Post installation, the engineer mentioned that he could not get the ac checked as it was winters and the compressor would only function when the ambient temperature is higher. He told us to test the ac during the summers.
2. 16-may-20: when i used the ac for the first time during summers it did not work. Raised a complaint for the same and the service engineer from reliance filled the gas in the ac.
3. 18-may-20: ac stopped working again. This time the reliance service engineer did external piping and filled the gas again and charged inr 5, 750 from me.
4. 30-may-20: the ac stopped working again the reliance service engineer checked it multiple times and finally confirmed that the internal coils of the ac are faulty that is causing the problem.
Since then, they have not replaced either the product, or the coil. They are not ready to refund the amount. Moreover, the service head mr. Manoj yadav, has stopped answering our calls.