Unable to access iCloud on iPhone 12 Pro Max after losing my iPhone 5

My iPhone 5 is lost I have now purchased iPhone 12 Pro Max I want to login my iPhone 5's iclose ID in it but Apple is not allowing it it is saying that my first mobile number we will send OTP on it and enter it here then it will be in but that number was lost along with the mobile I got it Couldn't get it, now I request that I have a WhatsApp of this number, if you send me the OTP on WhatsApp, then I can load my old one, thanks.