Exchange required out of the new batch iPhone6?!

Hi,<br> <br> I need to find out, what's the issue with iPhone 6 as my 1st iPhone was replaced after 5 days due to the squeaking screen on the right hand side from the button, now 2 weeks later my replaced model has even more irritating squeak where left side of the screen isn't glue properly again, I can see a small gap on the side? What is the solution as for R13k I say it is unacceptable? And I am not willing to send it for some assessment via MTN again for 5 weeks to get it assessed. As the phone was in the cover from day one, it is also in spotless condition and never was dropped. Please comment and advise on solution!<br> <br> And I am assuming it is linked to flex in its structure?! I moved from Samsung S4, which was much cheaper phone, which didnt have any issues related to its structure quality.<br> <br> <br> <br> tx