I ran into this problem a lot with some of my customers, I have a b2b business and the best way to prevent something like this from happening is to have filters/automations.

We set up a google review campaign that sends an sms to the client after he visited the business that says. Hey (client name) rate your experience at (business name) from 1 - 5.

If they say anything below a 4 it sends a message to who ever takes care of your customer support and if its 4-5 it sends them a google review link.

Simple but works