Can't verify code to sign into iCloud Keychain

So this is the second time this has happened to me now. I had changed my phone number without remembering to update it in my apple ID settings. I did a clean install on my macbook and when I go to system preferences, iCloud, and keychain and hit options it asks for my password, a pin number, but then sends a verification code to my old cell phone number. I call Apple support and they don't seem to understand what is going on no matter how many times I try to explain it even if they go so far as to share the screen with me. Their solution for tonight was to reset my keychain and lose all my passwords which I'm not even sure would have fixed the issue. I have updated my phone number in my Apple ID but it still won't go through to keychain to text a verification code to my current number. This is a huge problem and it needs to be addressed and I'm sincerely hoping someone out there has a fix for it.