Coverage expired

Where, exactly, did you buy it?

Odds are you bought a gray market phone from an unauthorized seller.

The warranty clock starts ticking the date it's originally sold by Apple or an authorized retailer.

iPhone 13 was released 2 years ago. If you bought this phone from someone other than Apple or an actual Apple Authorized Seller, the coverage on the phone started the date it left Apple's inventory. Its very possible your phone is out of warranty if this applies to you.