Van Echten was thankful none of the staff involved needed hospital treatment but said the whole team was "shaken" afterwards.
"The safety and wellbeing of our team is always our top priority.
"Our team are still shocked by this unprovoked incident, and we are focusing on supporting [them]."
The store was closed shortly after the alleged assault but reopened yesterday. Additional security is in place 24/7 for the time being, van Echten said.
Police said they were sent to the store after "an altercation between a small group of people and another person in the store" shortly before 3pm on Friday.
"The group left the area in a vehicle," police said.
A spokesperson said no injuries were reported, and called on anyone with information to contact them.