As long as the brand exists, the owner needs to invest in ORM management. It is because a negative brand reputation affects the business beyond repair. One must thus, constantly maintain and monitor his brand’s reputation. However, as per your convenience, you can always opt-out of ORM services.
You must notify them of the reason for opting out of their services. If the issues can be resolved, it will be a win-win thing for both parties. But if not, you will have to give prior notice (of about a month) to your ORM service provider before terminating your ORM contract with the company.