Iphone 10 and Security Update

My Iphone 10 is less than 1 year old. On Sunday, September 12th, I updated my phone because of a 'security update'. When I checked on my phone the next day, there was a message saying my phone was inoperative and probably needed repair.

I took my phone into a recognized Apple site, and they did diagnostics and said it was a hardware problem. The only solution was to turn my phone in for a replacement at $500.

However, he said, the new Iphone 13 was announced today! I could buy a new phone.

Gee., what a coincidence. Now, I'm working with an old Iphone 6. My Iphone 10 will, sometimes, get me on the internet and, sometimes, will do mail. But no phone service.

Has anyone experienced this problem with the latest security update? My phone is less than 1 year old and it craps out.