...without making your customer service person want to kill himself.
I honestly think that "The customer is always right" is the worst phrase ever invented. Why? Because it makes customers think they are entitled to treat other human beings like crap, just because said human beings happen to work in a customer service position. I generally alter the phrase in my head to say "The customer is rarely right and usually stupid." Rude, I know, but it makes me laugh.
Things go wrong. I get that. And as a customer, I like for things to be made right. However, there is a right way to go about getting things made right. The main point in mind is to keep calm and be polite. You can make it understood that you are not happy without blaming the person you are talking to.
This work week has been hell. I'm looking forward to the end of April when I can quit my job to move on to greener pastures (in Korea, natch). I've had two particularly rotten customer experiences that illustrate how not to complain.
I had a reservation check in about 1AM. I was in the middle of cleaning the lobby. I got the lady checked in, gave her a key to the room and locked the door behind her after she left. I started vacuuming. I stopped a couple minutes later when this lady knocked on the window. She told me her key didn't open the door. I apologized and asked what lights flashed. I ask this because sometimes the door doesn't close all the way and a jerk on the handle solves the problem. This wasn't the case, so I made a new key. As she left, she said, "This better work. It's late and I'm tired and just want to sleep. I don't want to wrestle with the door." I understand the frustration, but it was not my fault she arrived so late. And I have no control over the door locks beyond simple fixes and making keys. I watched as she opened the door, just in case the new key didn't work. She got in fine. But it was unnecessary to blame me for the problem, as her tone made it clear she was doing.
The following morning, I got a call from an irate guest. "My shower went cold. I can't believe you charge so much for a room and then let us take cold showers." It was my fault the shower went cold, rather than the result of half the guests in the almost full hotel taking showers at the same time. And yes, taking a cold shower isn't fun, but there's no need to call the clerk and chew him out for 10 minutes for something he has no way of controlling. To be honest, I don't really feel bad for people who get cold showers occasionally in hotels. For two years in Peru I had cold showers, when I happened to have running water.
To sum up, if you're unhappy with a service or product, state your complaint in a calm manner. Don't flip out and start ranting. It serves no purpose. If it's something that can be fixed, ask for the situation to be resolved. If it can't be fixed, ask if a refund or reduction in price is possible. The calmer you are, the more likely it is that the person you're complaining to will be willing to work with you.