Consumer Redressal

My mom is using micromax a65 bolt mobile. She brought the mobile 3 months ago, and since then she has given the mobile 7 times to service. They take the mobile saying that next time it wont happen and when they give the mobile its the same outcome. Mobile hangs, applications not working, internet not working properly. My mom is fed up of all this she cant deal with them anymore. Please kindly take some quick action so that the coustemer service deals with all their clients safely . I had also wriiten an e-mail to the head office but from there also i did not recieve any reply. I request you to kindly take some stringent action.