Iam using sonny ericsson Z550i it has fallen down

I want you to know that when a cellphone got fell badly, the hardware inside your phone got misaligned,like the LCD,microphone or the speakers inside of it or some parts of it maybe got broken. There is no serviceable parts inside that you can handle by your own. My suggestion for you is that bring the cellphone to the nearest cellphone repair center in your place. The technician will have to do dismantling your phone and fix the problem.