Verification code sent to old phone number that is not even registered in icloud

I’m trying to set up family sharing as I have purchased a iPhone for my daughter.

She already has an account that I created a while ago (and set up a family sharing, etc).

As I'm changing her account date to her real date (and she is a child), I am asked to verify the account with a code that is sent to a phone number that I do not have anymore. The strange thing is that i have already updated my icloud some weeks ago with 2 other contact numbers and with other several iphone/ipad under my account, so in theory there shouldn't be any trace to my older phone number. For some reason this verification code is automatically sent to my older number and there's no option to ask to have it sent to my new numbers or to any of my authorized devices.

Please help me solve this issue.

Thanks