change keychain verification number

ROr some reason my verification code is being sent to my ad number but anyone who has one will know that it doesnt accept text messages so I can understand why it's being sent there. Then I'm having the issue that I can't change it as on the support page it says to go into advance for Keychain but you actually don't have that option so therefore it cannot be changed. Is there any way I can change it without calling apple support? Go in store maybe? I just want to link my keychain across my devices, not much to ask, but I'm not waiting 2 hours to talk to someone on Apple support!