New phone for repairs handed back broken

A three week old I-phone without any physical damage 4s was handed in on Saturday 26/09/2015 for a screen that was locked and would not unlock.<br> <br> When I received it back on Monday 05/10/2015 I was told there was nothing wrong with the phone,but the screen was cracked and scratched.<br> I complained on Tuesday 06/10/2015,but was only told that my complaint was escalated to the head office.