Sony Z5 overheating again!!!!

I've bought a new Sony Z5 16 days ago. Gave it in the 2nd day because the phone overheated like crazy (had a Sony before and my husband got his Z5 same day from mtn) had to wait 14days and got a new Sony. Day 2. It's overheats again. The battery doesn't last at all. My hand actually starts to burn. How is this acceptable? Now I have to give it in again and wait for another 14days for a phone that I've paid in cash. I have to pay for the screen protector everytime also ? I want my money back!! Very disappointed!! Don't want to repeat the process again!