It should at least let you back up and download your follow list. If you want you can use the results it generates to manually remove individual users by clicking on their profiles directly. This isn’t ideal, but it will help. I can assure you it works just fine for most people so it’s likely some local configuration problem.

Yes, as I said, it does everything except delete, either individually, in batches or nuclear. I did delete a couple by flicking between the website and #Amethyst. It's a cool little tool otherwise. Who doesn't want to kill zombies?