Ombudsman services are able to resolve conflicts where the customer and business don't agree. They're appropriate for regulated businesses to draw a line in the sand as to what is a legitimate complaint by independently settling cases where the customer and business did not agree. If the Ombudsman hears 100 unresolved complaints and upholds only one then probably the ordinary customer services are working as intended. If they uphold ninety nine something is gravely wrong with your customer services and the regulator needs to step in.

This isn't so dissimilar from the method used in pathology to deliver consistency in results across multiple labs and assay methods. You identify some boundary cases. This is definitely normal, this is definitely cancer but this is borderline, repeat a few times. You replicate and get all the labs to mark your samples. Then you can identify labs (or assay techniques) that aren't reliably putting things in the right categories and demand they improve or stop.