i was having problem of battery of my mobile i12, given for repairing after few days they call me th

i was having problem of battery of my qmobile i12, given for repairing after few days they call me to collect as it has been repair I bought it Saturday evening and I faced little difficulty within 2 hours that my voice mic isn't working but next day was Sunday, so I went to office 2 complain it but they charged me again as i charged 1350 before. Please look forward it becoz I don't feel that it works well afterward too. Thanks