Karbonn Mobiles — Complaint against service center

R/sir/madam I purchased a karbbon titanium s5 on[protected] it give a sd card problem from starting i submitted it in first week of January and i get back it in last week march and thy say we change its mother bord but when i use the phone the problem is not salved after that i submitted my phone on date1-5-2014. they say it will be replaced by company and say it get back shortly but now he say i will take 30-45 days . sir please help me and take strict action aginest karbbon regards, suresh kumar