Actually, this is misquoted. It should be, "The customer thinks he's always right especially when he has acted like an ass and nobody wants to help him."

Now, having said that, we will spend some time educating you as to the proper etiquette regarding asking for help. You cannot talk your way out of situations you behaved your way into. Be civil and gracious and people will beg to serve you.
There are always at least two sides to any story and the only mistake you made was not in naming the company you had dealt with. When airing greivances in public, it is wise to cover the bases first. Stating your opinion in a public forum without facts to substantiate your claims could be viewed by some as slander, a very serious crime. Don't believe me? If Man-A-Fre could prove that you hurt their business by posting your opinions without proof, you could be held financially liable. If you post, back it up. Steve-O is a pretty well respected guy who tries to resolve issues on the forum. I have had a few minor issues with Man-A-Fre, as have other, but there are proper channels to pursue before spewing your hatred upon the forum. We even spent money there before complaining, unlike yourself. You are obviously too important to be helped by lowly customer service reps as you indicated when stating the customer is always right. Try that at McDonalds and you'll get a surprise in your BigMac.
They may have given you the needed information and answered your questions out of professional courtesy, but I'd bet that you are they guy they laugh about around the water cooler. I don't believe that they had any problem with the spindle or tire carrier. I think that the problem they had was with your attitude. Do you sell these things for a living? They do. Do you install these by the dozens? They do. As a result, it might be easier to ask with thankfulness if somebody can help your plight rather than acting like a bull in a china shop. You may win the battle, but it looks like you've lost the war. Humility goes a long way on these forums. Get pushy and ungrateful towards people who give of their personal time and effort, or professional time and effort, and you will be spending time in the rain trying to fix problems that might not have otherwise existed.
Now repeat after me, "I'm sorry that I get a little worked up at times. I will listen more and talk less. I am not an expert but I realize that you have information that can help me and I'm grateful that you will spend some of your valuable time to help me. I know that I didn't buy the part from you, but I'd be a happy and loyal customer due to the time you have spent educating me. I will not badmouth you, rather, I will talk to you and find out why we are not on the same wavelength. We will then solve our problem together. Thank you."
Learn to say these things and you'll go far in life. Don't and you'll only hurt yourself in the long run. Be careful who you step on when climbing up the ladder of success. They are the same people you meet on the way down. Stop burning bridges. Mend fences and you'll go far. Now, go forward in life and don't bother arguing about content in this post as you'll lose whatever precious little credibility you might have left. Good luck.