[Resolved]  Nokia 5300 — low battery backup.

Nokia 53OO — Battery Back up very low

Respected Sir
I have purchase nokia 5300 from delhi about 4 months ago I have submitted the mobile phone thrice to nokia customer in Agra and delhi but I am not satisfied by the service they have provided. In the last time when I deposited my mobile phone they have charged Rs 850 from me as they say your mobile has lost its warranty because of physical temparing but sir I want to say that I have not open my mobile phone personaly it is only opened by nokia care engineers.
Now Sir what should I do in this regard . I want your help

my nokia 5300 xpressmusice does not working since 3 months

my 5300 easy low battery...
charging fully only need 0ne and half hour but can only use for half day...
easy low battery...
how can i do???