Samsung Guru Muzik B519 mobile phone

Since i am using this phone from Jan2010

There is not proper batterey back up service personal suggest to switch off and put for the charge early min 4 hours required for full chargeing

After one month use i am useing for relinace CDMA No i had problem in call history, afterwards i am getting complient from callers my voice is very low some times nothing auidiable, i went to service at CTC at Secunderabad they are reinstal the softerware (saying upgrde) in this sequience i lost 500nos ph book they are not even bother to provide back the phone book, siply they show their notice board they will not take any precaution about all this mischefes. finaly i felt its rectified the problem

Than with in a week again repeated the same problem again they reinstall the software.

Even through i am getting complints from some of the callers they are not able to hear properly

I purchsed this moble from BIG C in SP Road branch @ Rs.2800/-, when i bring this to their notice, they are not responsible of any of these problems

Kindly advice me. how to get out of this is any body want to buy i will ready sell for to reduce this headache