Company can't provide me the spare part

I purchased a Bajaj 160 bike in the month of July. After purchase, I noticed a manufacturing defect in the bike, as a part of it was bent. I informed the Bajaj Auto service centre about this defect. The service centre told me that they would need 10 days to order the required spare part. However, it has now been 20 to 25 days and nothing has been done. When I call the service centre, they say the company has not provided the part yet and that I need to wait further. My bike has been left at the service centre all this time and has been exposed to rain, causing further damage to it. Since the issue has not been resolved despite my repeated follow-ups, I am now demanding a full refund for the bike. If a full refund is not possible, I want Bajaj Auto to take immediate action to fix the defect and return my bike in proper condition without any further delay.