Apple India — not satisfied with the resolution by snr engg team

I own iphone 7 256gb and facing an issue of battery drainage in standby mode as well shutting down at random viz 20% after long wait and discussion with apple snr engg team they told to replace the device and as its oow so costing me 35k unbearable just after 18 months of the device and the issue was reported to the apple in 14 months of the use of cellphone plz look in to the matter cid[protected]