The documentation for unbind-service does not match the usage.
The bind-service command.
The Syntax in the document and the usage indicates an OR option: <TargetESPBindingPort | TargetESPServiceName>.
But, the description in the document uses 'and':
"You must also provide the Port on which this service is configured to run (the ESP Binding), and the name of the service you are unbinding."