Apple India — delay in returning my phone.

Address: Srinagar, Jammu and Kashmir, 190001

My iphone is under warranty and because of some reasons it's capacity went down to 85%. I then went to authorized apple service centre in srinagar on 1st of november. Then they gave me an expected date on 15th of nov. But it's 25th of november and they are returning my phone back. Battery replacement of phone takes a max of 45 mins but i'm awaiting since 1st of nov.