9. Complain well
I work hard for my money, so when I buy something, I expect to get what's promised. If I don't, this squeaky wheel complains loudly and smartly. When I call the 800 number, I always ask for and take down the customer service representative's name or employee number. That way, I know I'm far less likely to be "accidentally dropped." Always prepared for a long hold, I use a headset when I call and multitask.
To speak with a person I know will have more power to solve the problem, I immediately, but politely, ask for a supervisor. If the person I'm speaking with declines to connect me to a supervisor, I inform them that I guess I'll need to send in a letter asking why (naming the rep or referencing the employee number) denied me access. That always seems to work. In the complaint, I try to give the important facts in a very calm manner, sometimes noting I'd like to get a response from the CEO as to why this happened. Usually, the supervisor wants this to go away as much as I do, and will offer a solution such as refunding the purchase price or replacing the item. And if you still don't feel you've gotten satisfaction, the internet is a great equalizer. The possibility of having bad customer service facts posted where everyone can see often adds leverage. If this becomes necessary, make sure you post just the documented facts and don't make it personal.
Payoff: Varies but, when I toured a timeshare for a promised carnival cruise, I turned the worthless voucher into getting reimbursed for the actual cruise.