I work in the headquarters of a company that is federally licensed. Our company sells retail to customers, and has extensive customer service available. However, since we are federally licensed, our company has a headquarters contact number available through that licensing bureau, which rings here in my office, and also a fax number, which comes to a fax machine also here in my office.
We had a gentleman that started faxing us complaints about a feature of his service with us. Think something like his e-mail wouldn't load pictures, but otherwise worked - that sort of thing, easily diagnosed by customer service, but not at all something falls under a federal jurisdiction. He would send us pages and pages of complaints - always overnight, as I assume his fax machine was set to the 'toll saver' overnight fax option. Since I work in HEADQUARTERS - I can't see his account. I don't have clue 1 as to how to fix his problem. And he refused to call customer service! It got to the point we were sure he was either delusional or playing an elaborate practical joke - it didn't help that his company name, while also appropriate for his industry, sounded like a sexual innuendo or the name of a bad adult movie (a la 'Shaving Ryan's Privates' instead of Saving Private Ryan).
We sent him pages, and pages, and PAGES of suggestions from our company's FAQ online, with links to the FAQ, to the customer service pages, sent him phone numbers and e-mail addresses . It took nearly two months to get him to stop.
Out of curiosity, one of my coworkers called the customer service supervisor in the next building and asked what the fix was for the problem. Turns out he needed to enable a setting on his device - would have taken 30 seconds.