Just received this from support in response to my support query:
There is an ongoing issue with the app, the tech team are aware of it, and are investigating.
The account is still available online, so you can still log in that way to manage the account in the meantime.
You could even save the https://48months.ie/auth/login shortcut to your device so you can use it to log in each time you need it.
Hope this helps.