I’ve had the luck to be able to work over the past 13 years in jobs that require direct contact with clients and their demands and complaints.
Over time I’ve learned that there’s only one thing you can do to them: be fucking nice.
Why sould you be nice when someone is screaming at you? Why to be nice when they insist on talking to someone else because you’re incompetent? Because they would not be able to complain that you treat them bad, they only will have the fact that they didn’t get what they wanted, which is usually something that no one can give them, even the owner.
As a service provider or worker the way to deal with this type of people is to remain calm.
1 – At the minute someone has a complain, put aside what you’re doing, even if you’re speaking to the President himself. They are going to feel (a little bit) better at once.
2 – Explain them with detail all the steps that you both must follow to be able for you to do your job and for them to get a solution. Don’t tell them things like “you have to pay and then we’ll see…” tell them instead “Our policies are as follow: you have to pay for the service and, if you want to, the manager/owner will contact you.” The worst answer to any question is “I don’t know…”
3 – If they start screaming at you of insulting you, remain calm and tell them that if they keep screaming or insultin you, you will not speak with them (as screaming is not a behaviour expected for a grownup person.) This works about 99% of the time and if they can’t calm themselves, they will bring someone who is to deal with the issue.
4- Try to find a solution for yourself. If they insist on talking to someone of a higher position, call someone who can provide you with a quick solution or talk with the client to explain them what you have been explaining. Why does this work? Because they feel the manager/owner is more reliable than you… even when he/she tells them the same.
5- If nothing works (which are the least cases), tell them that they need to leave. At this point there is no no more you can do and its not woth even trying anything else. Do it politely and wish them a good day.
If despite this they complain in social media (Facebook, tripadvisor, etc) answer them (politely, again) explaining everything you did to help them. Try not to apologise as they will feel they were always right.
Be Fucking nice all the time. They can’t complain you were a bad person even if they try to.