Faulty iPhone 6

After phone was recieved phone immediately started to give problems with the screen. As i went on holliday could only bring back phone on day 8 after the 7 day excange period. Phone was booked in and Software reloaded. Phone came back and problem still occurs. Collected phone today after 3 week wait. Software was re loaded again. Aswell as glass screen protector was removed and broken. Manager said they not responsible for this. In the 2 months. This phone was booked in twice already. And was told by the manager i should take the phone directly to vodaword and they could excange the phone for a used unit. This is not acceptable. I want a new phone and screen protector now!