Q: Same loop as before... setting up iCloud/keychain

I asked how to change the phone number (old, not used) that the iCloud (keychain) was pointing to (in a previous message) The answer given me was go to iCloud setup and change it there in keychain setup. After finding out how to get back in to my computer, after it locked me out, causing me to scramble to find my name password combo (that I haven't used for years)... I am no further ahead because I get in a loop, both on my iPhone and on my Retina MacBook trying to set up keychain!!! As I said before, I had changed the phone number in my Apple account from my Retina MacBook... when the setup window message (on my iPhone 5 and my Retina 2013 MacBook0 says to install the code that might take some time to arrive... it never does because it says it is trying to send to the old Phone number). It asks if I can't access the iPhone, follow the use password feature... causing the loop to begin all over again... sigh...