Kult Mobile Company - delay in providing services

i have kult beyond mobile imei no *************** on **.*** my mobile faced a battery swelling issue so i was handover my mobile in to kult authorized service center that time they say we replaces in a battery with in a week and they collected a amount of *** rs out of ***rs. but still till a date they say battery has a no stock. i already talk with kult customer care executive but they also say no stock. the lame reason creates a mental agony.