Trello thought my one account is two accounts and now I can't access my own board

[ruthamey]

I have a Trello account with my work email address and my Trello account is managed by my institute, i.e. it says 'Your admin now manages your account.'

My work email can either be username@institute.ac.uk or the alias initial.lastname@institute.ac.uk, both come to my same inbox. Somehow I managed to at some point set up an Atalassian account separately for each, each with their own set of Trello boards. I have an important board on my username@institute.ac.uk account, but when I try to log in with my username@institute.ac.uk account it logs me into through my institutes single-sign on and will only log me into my initial.lastname@institute.ac.uk account. So I can't access my important board as it's on the other account... which I can't log into...

I have the url of this board I need and when I tried to open it I had to send a request (to myself) to request access. The request came through to my email and I accepted it, but because I am no longer able to log into my username@institute.ac.uk then I can't log into accept the request. It's stuck on 'Request sent. You'll get an email if you're approved to join'.

If anyone has any suggestions on how to access this important board I'd really appreciate it! Many thanks in advance for your help.