Is there a phrase like "preaching to the choir" but with the opposite meaning? [duplicate]

I have found "Whistling into the wind" online but I do not think it fits because it seems to mean that your words are not heard, whereas the opposite should mean that you're being informed by someone of a 'fact' with which you strongly disagree.

I generally respond, "you're preaching to the choir", when somebody 'vents' to me about something that I too take some issue with, which may be an evolution of the idiom used when you tell someone something they already know, rather than something they agree with.

Solution 1:

I think casting pearls before swine is a good opposite. It means giving advice, guidance or direction to those incapable of appreciating or acting upon it.

Solution 2:

I say "You're banging your head against a brick wall" or "You're wasting your breath".