Xiaomi India — Charging issues

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New Delhi, Delhi, 110009

I've purchased a redmi note 2 prime 4g from amazon.com.. Recently some battery issues have popped up. When the phone is in charging mode it charges very slow and the battery gets discharged very quickly...i did tell my issues to customer care through toll free number and they recommended me to use another with 2amp specification, but it didn't work ..please resolve this issue..
And is it possible to get a replacement for the battery? as my phone is in warranty period...
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