The first rules are the most important and basic, but bear repeating, as they are often forgotten.
When dealing with customer service over the phone
#1 Be nice.
#2 Write everything down.
FiveCentNickel has more in their step-by-step primer. We’ve covered every item individually at some point, but it’s nice to have one handy locale.
Solving Customer Service Problems [Five Cent Nickel]