How do I add license keys to a company account

Hello,
I have 2 ETS5 Supplementary license keys that I would like to add to our organisation account.  
However, after clicking the obtain button I am informed that 'The code you provided was incorrect.'

They may already be linked to another user within the same organisation who has now left.  Also we may already have an older organisation account on the system (which I've would have now duplicated), but those login details have been lost