Nokia 2310
Keypad lock not working

I am submit my handset to nokia customer care in sakarpur, delhi for 4times but always the same problem accured next day, then after I, m give my handset for 2 weeks then they gave my handset yesterday, today the same problem will be accured and 1another problem is also attachedwith that low sound. For that I, m come to varun enterprises to say that but there is no hearing of my problem and behave rudely