No Service at All

Have visited the istore in Eastgate 4times in exactly one week to sort out my new ipone 6. Had the new phone for 2days and crashed. They refuse to help me and has to check the phone before replacing.. That is after some one has decided to help me after waiting 20minutes for assistance. Oh yes.. Then when they eventually help me the first thing they tell me is that I need to make an appointment. I have paid cash for my phone and this is the service I get? Replacement policy?????? Please????