Consumer Redressal

Dear Sir, I brought an apple cell phone 5 months back. After a month there was a problem with the phone and they replaced it. After the replacement the cell phone is having repeated problems. They have given me a faulty phone. I have already got it repaired twice and now again there is a problem with the phone. I spoke to the customer service department and they are fooling be be saying its a software issue happening because of the operating system. If it is happening because of the operating system the problem should be all the cell phones Apple manufactures?I am having a very hard time.They have cheated me.Can you help me out here? Regards