If these companies are wise they will monitor the internet for complaints such as yours. Just as in the real world these folks need to understand that we have options, and poor service, rudeness and broken promises will put them out of buisiness just as surely as it will a brick-and-mortar buisiness.
I'll lodge one of my own. Two weeks prior to our honeymoon we ordered o-ring chains and new sprockets from Power Motorsports, via Amazon. Mostly due to the fact that o-ring 428 chains are not in-stock items to my local retailers and the fact that we had plenty of time, so why not save a`few bucks in the process.
Power Motorsports showed all parts in stock for immediate delivery. After more than a week had gone by we attempted to check status on our order. Power Motorsorts would not return our calls inquiring about the late delivery. We lodged a complaint with Amazon who in turn contacted Power Motorsports who claimed that the parts had been shipped.
Two days before liftoff, Power admitted that they had not actually shipped our parts at all, but had rather "shipped" our incomplete order to themselves, pending availability of two extra master links we had ordered. Basically they had lied to Amazon by using the semantic "shipping" term. They finally admitted their deception on the Thursday evening prior to our Saturday wedding.
Our local dealer worked a minor miracle by gathering all of our parts from several different sources (i.e. one chain from one source, one rear sprocket and two fronts from another, etc.) and had them shipped overnight from all these various sources in the nick of time to save our trip. I spent the night before our wedding swapping out chains and sprockets thanks to Power Motorsports and I don't give a rip if it's an isolated incident. They'll never see a dime of my money again and I'll tell anyone who will listen just how much they suck and feel quite justified in doing so.
Moral of this story is that when you get burned you have a duty to be vocal about it. IMO at this point in the game you're generally still better off going through your local dealer if you need something immediately, reserving online purchasing for when you can afford the possibility of getting burned or receiving substitute parts in exchange for rock-bottom pricing. I've found that some of these online oufits actually charge as much or MORE for the parts than your local Yamaha dealer.