Faulty Devices

So In a period of just 1 year I have had 3 Apple iphone 6. They were returned for being faulty<br> I am so upset as the iphone that i was given now is also giving me problems. the front lense of the phone is starting to moving out of place. meaning this will be my 4th one. Once the warranty is over vodacom will say its no longer there problem. So before this warranty ends i demand a better phone as ive been given faulty phone. this is unacceptable. in a space of just one year 3 faulty phone. <br> SO EITHER you give me A better phone or you cancel this contract. I am now sick of this