What do they hear when you say "Agile"?

If all you tell external stakeholders is that you're doing "Agile", don't be surprised when they act in ways inconsistent with how you are working (e.g., requiring extensive documentation at the start, committing to unrealistic schedules, etc.).

When you said "Agile", they probably interpreted the word in such a way that was most convenient for them.  It is highly unlikely that what you meant by Agile and what they understand as Agile are the same.

Instead, I would suggest getting together and describing the specific behaviours, protocols, expectations, etc. you would like to see.  It's likely that they won't agree with everything you propose but at least now you know there is a conflict and you can work to come to a mutually acceptable alternative.

Don't talk about Agile.  Talk about specifically what we want to do and why we want to do it.