Like I said:

Let your players still have their agency; don’t just declare that it doesn’t work (unless you all wanna agree to house rule that it just doesn’t exist or something).

Like I said, I agree with you about not just cancelling it entirely unless there's an OOC discussion about making a house rule about it.

You can't let the players ruin your fun (and, likewise, their own, because it turns a challenging situation into some stupid anticlimax and basically removes curses from the game as a mechanic). Likewise you can't ruin your players' fun and just unilaterally say this curse is removal-proof. Fortunately, there are multiple middle ground third options available, that preserve the fun for all parties involved.