"So sorry, I didn't see the 'no bicycles' sign."
"State law qualfies me as a vehicle."
"Would you prefer I wheel it inside on your (probably un-) mopped floors?"
"Your being officious is taking time from others and keeping cash flow at a mînimum."
Etc.
The window jockey had a bad day, maybe doesn't like cyclists,... sorry he took it out on you....