Use in-app chat or email hello@monzo.com, letting us know the email address the person stuck in the queue used to sign up.
Golden tickets are a little buggy right now as a result of us turning off the issuing of new tickets due to this and the impending current account release.
I must stress that existing golden tickets should work, any non-working golden tickets are an unintentional bug.
It’s worth noting that golden tickets delivered over Facebook Messenger and sometimes WhatsApp will still appear as used due to Facebook stripping out a few key parts of the URL. Try sending the golden ticket another way if you have that particular issue.