How can I renew my AppleCare+ for my iPhone 13?

Worth a try......

Purchase the new coverage within 45 days after your original coverage ends. To find out if you can purchase the new coverage, go to mysupport.apple.com and follow the onscreen instructions. The new coverage automatically renews until canceled.

If you choose to add coverage, your coverage will be subject to the then-current AppleCare+ Terms and Conditions.

Just contact Apple Support and plead your case. You may be able to make up past payments and renew your coverage/warranty.

If you’re in the US please call 1-800-MY-APPLE or outside the US, consult the support articles below.

Contact Apple for support and service - Apple Support

If it has expired, you should be able to renew on your device, unless it has been too long that is has been expired. See the information here, Extend your AppleCare+ coverage - Apple Support

How long ago did it expire?