Unable to register AppleCare+ for my iPhone 13 Pro Max.

i bought this iphone 13 pro max with the apple care + with theft and loss and i pay 13.49 $ monthly and i have the agreement/policy number and the serial number for the phone

so they took the 13.49 $ from my bank account and when i wanna connect the apple care with the phone

i have a red massage saying that this serial number doesn't have an apple care + with theft and lost so what shall i do because i bought the device with the apple care + with theft n loss and it's not taking it

[Re-Titled by Moderator]