I'm sorry to hear you are having this issue. I have seen this a handful of times with other phones. To save you the time of trying to troubleshoot the issue, I would recommend going into an service and repair center so they can test the battery and the phone. Below is a link to our store locations. please select the radio dial that says repair to give you the correct listing.
I would advise you to go to a Sprint Service and Repair store so they can test the device and the battery. It could be one or both.
Hope this helps,
Sprint Advanced Tech Support
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