iStore pre-owned shop ****

I bought apple iphone11 pro max from the istore pre-owned store. Phone was delivered on the 24th of April 2024 at 11:15am. I charged the phone and the apple icon went then off again. I allowed the phone to stay in the for 2hrs and the apple icon was just going on and off. I then reported the faulty phone, I was sold a phone that is not working, not even switching on. I was then advise to send a mail so iStore can arrange pick of my phone. Mail was sent and waited. Am still waiting for phone to be picked up since the 24th of April. I've been calling istore everyday about this and al told my query is being escalated. Am sitting with a phone that is not working and paid in full cash. Do not purchase a phone from iStore pre-owned shop cause they sold me a dead phone.