Apple India — battery

Address: 604204

Dear sir
[protected]@icloud.com it's my apple I'd. Past 6 month I was using I phone, i have facing some problems on my apple iPhone 6s 64gb.
My mobile getting fast battery drain.i had turned off commonly battery using apps everything in the settings. But also having problems.
If I has 100% charged. continuously using 4G or 3G means with in 2-3 hrs battery level come to 20% below.
Normal Samsung or chaina mobile having greatest battery back up. this f...ing iPhone gets me irritating daily. Mobile Cost is high. Fu..ng how Many times should charge per day. Please resolve my problem otherwise I'll go for Samsung or some things else. I never promote any apple devices to my friends or relatives.. Hope u can understand my problem