Customers are usually really fun to work with, but sometimes you run into a difficult one, a classic "tough customer". So what do you do when you have to work with a customer who is a true bully? You know, the customer who throws his weight around, talks over you, raises his voice if you push back, disrespects you and insults you with aggressive behavior.
I've dealt with my fair share of bullies over time and learned the following approaches to defusing the bully behavior. Note, all these tips refer to "him". I have never encountered a female bully (I am sure they exist), but then again, I have not worked with many female customers, so I will say "him."
1. Get to know him
Most bullies have a hard time keeping up the aggressive and domineering behavior once they are on a familiar, social ground with you. Not always, but often. Invite your customer out to lunch with no agenda; don't talk business, just get to know one another. Be sure to ask lots of questions. Most bullies are insecure, so make him the center of attention. Ask about his family and interests, and listen attentively. You are more likely to enable him to relax around you, and you'll learn something new about him. This knowledge will help you connect with him in the future.
I had a customer in Arizona many years ago who was awful to deal with--short, angry and aggressive in every meeting, convinced, we, (the vendor), were trying to mislead him. By investing the time getting to know him I earned his trust, and we sold a significant contract to him. In the process I learned what he was deeply worried about; buying the wrong tool and losing technical credibility.
A word of caution--you need to be genuinely interested. If you are faking it your customer will know and you'll lose his trust.
2. Don't take his behavior personally
As I said, most bullies are insecure. If you watch them carefully, you will notice their behavior is no different towards you than it is towards other people. They tend to also bully those below them in the power structure. So while their tactics may push your buttons, or make you so mad you want to punch something or cry, (this had happened to me more than once), remember it is not about you. It's about him; his fear, his need to assert himself to feel better. Take a step back from the onslaught, take a deep breath, and let it go. This small gesture will turn into a big investment in the long run.
3. Get to know his boss and peers
This is your insurance policy. In most organizations the other people in his company will know he's a bully. They usually won't admit it, but they know. They might have a culture where it serves them to keep him around, or maybe they don't let people go, (more popular in the 80s than today) Find ways to meet and develop professional relationships with his peers. Discuss areas of common interest such as a mutual customer. Make sure you get to meet his boss, even if he keeps telling you that you don't need to (which is classic blocker behavior). This way you establish your own credibility, independent of how he portrays you. You will both gain from what you learn about the business as a result: you will be more useful to his company because you'll understand more of their needs, and your knowledge will help you cement a relationship with him when you are.
4. Stand your ground
With all that said, you do not have to cave and agree just because someone raises his voice, talks over you or becomes aggressive with you. If you are in the right on a discussion point, or you need your customer to understand an aspect of your work together, hear him out and then gently assert yourself. Let him talk, let him bluster, wait him out. Don't disagree or cut him off or he'll increase his bullying. Think tai chi in your head. Let his energy flow over you, and then, when he gives you an opening, tell him what you believe he needs to hear.
5. Move on
Finally, sometimes you are just incompatible with a bully. Either you trigger something in him, or he triggers something in you. If you've tried building a relationship, you've been professional and diligent in your service of the customer, and still he's a bully then maybe you are not the right person to work with him. It's important to recognize when you can succeed in changing someone's behavior towards you and when it is hopeless. And if it's hopeless, stand down and ask your team to put someone else in instead.
Of course, if you are the CEO this is almost impossible. But even so, you can usually find someone compatible to front for you, someone you can bring into judicious scenarios and protect you from your bullying customer, and protect your customer from your temper!