Q: My new iPhone 6s Plus battery life indicator not responding. From time to time it got stagnant.

Hello abbyfromcheras,

I understand that the battery indicator on your iPhone doesn't appear to be changing. In such a situation if may help to switch the Battery Percentage indicator then restart your iPhone.

Show the battery percentage on your iPhone or iPad
https://support.apple.com/en-us/HT201102
 

Restart your iPhone, iPad, or iPod touch
https://support.apple.com/en-us/HT201559

Cheers!