RELIANCE DIGITAL - Defective Product Refund required

I purchased a Havells Cooler from Reliance Digitial website on ** Mar ****. Product deliver on * Apr ****, and it was dead on arrival. It was not working. I raised a complaint to Reliance on * Apr and asked for refund. Since then, I called them at-least ** times and wrote ** emails, but they are not willing to resolve my issue. Instead of refund they sent a technician on * Apr to fix defect. Technician came and informed me that there is major defect with product, and he replace Water pump and Sensor was fixed. After he left, the cooler stopped working again after * hour. When I reported for refund again, they are not willing to refund. They are saying that they will again try to fix defect. This product is third grade product will all sort of manufacturing defect. Even they could not fix it. I don't want to do multiple repairers to a Brand-new product.