Is Bring overwriting shipping method?

I’m trying to cancel shipping for certain products that can’t be shipped, via a plugin made for this (Flexible Shipping).

However, no matter what settings I use, I get the “pakke i postkassen” option.

Is there a way to fix this? I’m tired of disappointing customers who can’t have their orders shipped after all, because of the nature of the product (supposed to be pick-up only).