I hate to come across as the pedant (since I agree totally with what you are saying), but to clarify a point: you were not guilty of insubordination, since you were not a subordinate of the estate agent (well unless you worked for them, in which case you would have been).
I hate to come across as even more of a pedant, but I think that that was specifically the reason he chose that word; he was using 'insubordination' as a rhetorical device to describe the way he feels about his relationship with the agent, even if it's not literally true.
