There are no hard and fast rules for bending customer service reps to your will. Sometimes kindness will get you far, and other times it will just get you dismissed. The same is true for being gruff and to the point. Much depends on the personality of the CSR, the power the company bestows him with and the legitimacy of your concern.
An Awkward Sex and the City post (warning: the post contains some foul language) advocates the benefits of forging personal connections with CSRs to get them on your side.
After the writer’s iPhone broke, she was told she’d need to wait three more weeks to buy an updated model at a discount. She called Apple’s customer service line and sweet-talked the CSR, taking an interest in the rep’s poodle. In turn, the rep found a way to let her buy her new iPhone immediately.
Your own results will of course vary. If you find yourself on the line with a CSR who seems unwilling to help, you can always end the conversation and call back until you connect with someone more agreeable.
Uh, lets be nice, America [Awkward Sex and the City (warning: foul language)]