SHOCKING SERVICE OUT OF BOX FAULTY

We purchased a phone on 22/12/23 and after 3 days phone switches off whilst using then restarts. Took phone back on 26/12/23 for within 7 days cash back policy but Was told cannot refund monies as the phone must first be sent for inspection before anything can be done. After explaining it is within the 7 days after purchase we were told that is How it works. SHOCKING SERVICE