I seem to have been logged out of my Monzo account on my iPhone all of a sudden and when I try and re-authenticate by logging in with my email address, the log in email never seems to arrive. I have tried several times, waited for hours and checked junk mail but nothing appears. I am completely locked out of my account.
It looks like you are entering the correct email address. If you enter a wrong email, which isn’t registered with Monzo, you’d drop into the sign-in flow which involves entering your telephone number. This doesn’t seem to be happening so…
Is your email a personal account (gmail/outlook/hotmail/yahoo/etc.) or is it a work/student account (GSuite/Office365/.edu)?