Xiaomi India — redmi prime battery issue

I am using a redmi prime phone from more than a year. Battery of the phone started problem within a 6 months o[censored]se. So i visited a mi service centre in aligarh (U. P) for replacement of the battery, the behaviour of the staff was there very rude.in first instance they said company discontinued this phone so battery not available and after that they said you have to leave your phone here for 15 days for getting the new battery. They said this is our policy. Is it so? For getting a battery why i leave my phone there. The service staff's need some lesson how to talk to the customers.