There are several posts from these 2 accounts - https://superuser.com/users/238676/doland and https://superuser.com/users/238678/tyrone, in this question:
How to retrieve data from Firefox sync account?
I've flagged them, is there anything more I could do?
What should be done in general when dealing with these problems? I've never encountered anything like that in StackOverflow, does this happen often on SuperUser?
I learned about them because they also posted on my own question:
Why is deleting files to recycle bin so much slower than when using Shift+Del with Total Commander?