Lava Mobiles — mic problem with low output voice

Address:

91

I am purchaseing a lava a97 on april month, from the first day i am notice that my phone mic voice (Out put voice was too slow and i am give my handset to our nearest service center at rourkela for repairing... Till now i am given my mobile about 4 or 5 times but there was not any improvement in my mobile. Sir please do the needfull as soon as possible. My mobile iemi detail-[protected], model-a-97.