I don't think I am being unreasonable but maybe I am.
I have just paid a county council invoice and tried to email them a remittance slip (it's for work) to the email address on their invoice
It bounced back with this:
Your message to [email protected] couldn't be delivered.
The group admin only accepts messages from people in its organization or on its allowed senders list, and your email address isn't on the list.
I made up that email address. I did call, and the lady I spoke to took my message and the details of the remittance to pass on.
YABU - they don't want emails and that's fine
YANBU - Why list that email address if it won't work