We had a situation last year where a church I managed a domain and website for had changed their organisation structure and become an incorporated entity. As part of the restructure, their ABN changed (nobody was able to explain exactly why they were advised to change the ABN - but no matter).
I did not know they had done this, and of course, they did not know this was important.
So I received one of these emails from SynergyWholesale about their .org.au domain domain elegibility since the old ABN was no longer valid.
It ended up being a major pain - because usually these types of ABN changes are associated with a business sale or change of ownership and what SW expected was documentation to that effect.
I had to contact them and try and explain that there was no change of "ownership" as such - just a change in structure and so there were no contracts or anything of that nature. It took a bit of effort to make them understand to the point where they could advise on exactly what type of documentation would be suitable.
To make things worse, the change had happened nearly 2 years earlier - the secretary at the time of the change was no longer around and the new secretary was not familiar with exactly what had happened, or with all of the documentation.
Eventually we found some meeting minutes which mentioned the change of ABN and that satisfied SW to the point of being able to facilitate a manual CoR.
The whole exercise took over 6 months to rectify - if SW hadn't contacted us when they did, there was a good chance that the church would have lost access to their domain for a period. Not a huge deal like it would have been for a business - but still would have been very inconvenient.
So as much as it was a painful exercise, I was greatful that SW took the initiative when they did - it certainly avoided it becoming a crisis like it would have if we hadn't found out until renewal time.