Battery is not gving backup

Hi Team,
Mobile model : KARBONN K10.
IEMI : 910003120952364.
IEMI : 910003120952372.
I Have purchased the above mentioned mobile on Dt : 25/04/2010 in HYD (A.P). On the first day I kept the mobile for charging until the red light on the charger becomes green, this indicator is good idea. I am using this mobile in the same way but recently I moved to Delhi and now on the screen it got water patches (it has gap between the Display and the plastic frame) due to which the screen is getting spoiled and I have never dropped the mobile neither on dry ground nor in water.
Now recently from the past one week I am facing another problem , Battery is not at all giving backup for half a day and its gets switched off by itself while the phone is ringing ,however the mobile is not even an 6 months old . I even don't use this mobile for entertainment purpose nor I use this for long chatting.
I am sorry to say, I am not satisfied with this mobile and which makes me always think of it whether is the mobile switched on or off , I am very happy with my previous mobile NOKIA and I am still using the same from the past 3 yrs.
Kindly let me know what can be done by you to make your customer happy and retain the customer.
Waiting for your response.
Please feel free to call me for further Details.
Regards,
Sridhar.M
9811409022.