Requesting a refund...I want my money!!!

I took my iPhone's 12 pro max for screen repair. I called after 2 weeks to check if they were ready for collection of which I was told only one was ready. I went and paid for the "supposedly" repaired one. I asked them to charge it so we can test if it's working or not. The screen was not responding which is what the phone was taken there for. I then said I'll keep on trying to set it up on my way home as I was rushing to leave for Cape town. As I was leaving the mall I called to inform them it was still not responding I'll however return it when I'm back if the problem persists. I then returned it on Saturday and they **** and said it's the motherboard. If it was the motherboard it wouldn't even be switching on. They later changed to "your screen has a chip" which was also a lie. The screen protector had a small crack not the screen. The owner then said they'll try a new screen while I wait...the new screen was still not responding. He then asked his technician to atleast get the phone wirking by using my other phone motherboard which I just looked at him and said it's fine I'll collect it when it's done. When I call I'm told the screen is not responding as if it's my problem. The issue is their screen. I'm requesting for a refund and nothing else. I'm no longer interested in anything else. I'll take my phone's to iStore.