OnePlus India — Bettry drain and heating of phon

I hav brought nord 8 on wednesday.i hav Heard very positive views about one plus.so I decided to brought one' of them instead of iphone. Bt may be it's my mistake to choose one plus in place of I phon. Becoz my battery drain so fast .even 100%chrg will drain at the end of day .even though I m not using phon that much.my previous's bettry is much better than my new one plus though I brought my old phone 4year bt I didn't have to chrg my phon every day.i tried one'plus customer care bt no one talking to me and ready to solve my problem.