i see im not the first and a lot of people have same problem. I think that it should ask and bring that confirm dialog after when user is have to completed mosaic and won. That would be much better UX
How to reach rank 0 ? From all info that i have read you just need to do it same way as before, complete mosaic lvl 1 and then win 1 more game ( without losing).
I did this and was still rank 1.