Psychology Today has a piece on how to try to get customer service reps to help you when you have a particularly difficult problem. Summary:
1. Before you bring up your real problem, have the rep do a simple task (checking your email address, for example.) If you find the rep is being nice or engaged (or, for some companies, even awake), tell them you think they're being so good at their job you'd like to write their supervisor to compliment the rep on good service.
(Note: this may mean acting like you enjoy being polite and chipper to people whose job it is to get you off the phone as quickly as possible.)
2. Once you've promised them you'll do them a favor - if they're amenable to that, and some agents will see right through your facade - you've reached into their brain and poked their sense of social reciprocity. And they'll be primed to help you fix whatever problem which requires extra work.
At this point, if they "defect" on you and don't help you, at least you've gotten their name and supervisor's name, so that when you finally reach someone else who will do their job, you can track your own issue and know how many reps you've spoken to and who failed to fix the problem. For long term problems (and small claims court), this is essential.
3. If they do help you, you've got to follow through and contact their supe to compliment them. This method only works if both parties remain true to their word.
This part is the genius of the exchange: let's face it, that "extra" work really is that person's job, and they should really do it without you having to promise something up front. But now you have, and even though you "lied" to get them to do their job, now you've forced yourself to reciprocate after all. Even if you didn't feel like it.
And why not? You've reached into your brain and poked your own sense of social reciprocity, so you've primed yourself to do good. Pat yourself on the back for creating two wins where there had been none.