Only Google can delete reviews. Imagine if a business provides bad service and then deletes their bad reviews. How would customers be able to verify if a business is good or not? Put yourself in the customer’s position - How would YOU look for a service? Therefore, the reviews must be authentic.

The way to do it is to flag the review but they will only delete them if the review was fake, fraudulent or inappropriate. The only person who can delete the review is the reviewer. So you would have to approach the reviewer and try to resolve the problems with them.

Your other alternative is to start a new company.