Samsung Corby Mobile Phone — defective cell

Address:

Bangalore, Karnataka

i purchased samsung corby on 16/09/2010 from Chroma Electronics, Bangalore. After going back home we found out that FM was not working. So we went back to the same dealer on 29/08/2010 and he said FM signals are weak and the cell is fine, it does not have any problem. But problem persisted. so i went to the same dealer again on 8/09/2010 and they said they will rectify it and sent the defective cell to Samsung service centre.
one day later i got a call from it saying that motherboard has the problem so they need to open the cell and replace it. But i did not accept it. why should i pay the money for a defective cell? i asked them to replace the entire set and give me a new cell. hardly its not even a month and they say they can rectify it with one year service warranty clause. what the hell is this?? when cell is defective to begin with they have to replace it. means samsung company has sold a defective cell for right price.
How can i solve this issue?? please help me out...
thank you