phone now shuts down without warning; when batt isnt low

[gwaaama]

Not sure what I did (if anything) but my phone just powers off at 60% or 72% last time at 90%, and without warning. Is there anyway you can check my phone or should I go back to "Best Buy" where we bought our phones almost a year ago? This is a Samsung, AT&T provider.

 

[Hadron]

Is it possible that the battery is faulty?

If the phone is less than a year old (ie in warranty) I'd be tempted to take it back and ask. Back up your data first though.