After 8.1.0 oreio update of my galaxy j7 max, battery is draining too fast. In the battery usage list, android os and android system is getting 30% of battery. How to fix this.

Samsung Galaxy J7 MAX home key getting crack day by day. after one month of purchase,i saw one hair line crack. now it increased to 3 lines. don't buy J7 max. therefore Samsung rejected warranty for this.they told this is customer's failure.

I put the phone to Sri Lankan Samsung agent. they are very funny.they advised me not to use any 3rd party apps and don't use tempered glass to mobile. they said it can cause to phone stuck. I don't know what they mean.then full restored the phone and...

power off suddenly.(like sleep) can't wake up on time. but when i call from another phone,they can hear ringing beep.but phone will not ring or any notification.not wake up when charger is connected. after 1 or 2 hours it can normally powered on by p...