Boundaries at work

I’ve been experiencing overwhelm lately because I’ve been feeling like as my business grows, I’ve been having problems with people pushing on boundaries. For instance, just recently a prospect contacted us and when our receptionist tried to set an appointment, she refused to get off of the phone unless she put me on right then and there. For some reason, she didn’t believe that I could be in meetings for most of the day (typical for my field). She also sent an email Friday night, asking that I call her over the weekend and her frustration was on Monday AM when she hasn’t heard back. I don’t check emails after business hours and am not in a profession where weekend calls are typical.

Unintentional model:
C- my work day
T- people keep disrespecting my boundaries
F- angry
A- my brain starts a thought loop on how angry I am, I don’t focus on my work, I spend time talking about my anger
R- I get less work done, I am more frustrated, more angry, more overwhelmed.

I am having trouble with the R line in my intentional models
C- my work day
T- people see me as someone who can assist them with sticky situations
F- grateful
A- I thank them, I am understanding
R- ??

C – my work day
T – prospects don’t know the boundaries because they haven’t worked with me before **struggling with this because my boundaries would be typical of most professional offices — you probably will get a receptionist initially, you are not likely to get a weekend email response
F – unattached
A – I can inform them of the process without making it personal
R – ???

I appreciate your guidance!