I have not had this happen with my Curv-E, but I feel your pain! I have been exercising extreme caution with mine, and have experienced some very anxious moments when trying to remove some extra tight nibs.
It doesn’t make sense that the flange will have slipped out, so I agree with Erica to check back with Edward on this. Cost of postage for the return would be insignifiant in comparison to the joy of having this small masterpiece in good working order.
If, and only if, you were to hazard repairing it yourself, epoxy has always been my go to when fixing things with small surface areas that require a great deal of strength. More recently, I’ve discovered the magic of Gorilla Glue for strong repairs. However, neither will be pretty, and personally I would not take the risk.