Order Delayed.... Again

I placed an order for a Dell 500w power supply on May seventh. I have yet to receive the power supply, I've talked to Dell representatives on the phone and through email, five Dell representatives including my Account Rep, and no one can give me an answer as to why my order has not shipped yet! Every two days I'm getting an email that the ship date has been pushed back. I can't believe a resolution for this simple order cannot be found. I do not understand the disconnect between an account rep and the shipping department. I realize Dell is a large company, but if a part has been verified to be in stock by several Dell representatives I would think they should have access to the person representing the shipping department to track down a simple power supply and get it shipped. I purchase and support the IT equipment for the company I work for. The company that was an HP shop when I walked in the door. I've been converting all of our workstations over to Dell, as I've had such a great relationship with Dell and their products in the past. I had planned to order the other two-thirds of those replacements workstations from Dell this year, but if this is the kind of customer service Dell is practicing these days, I don't know if that will happen. I pray someone from Dell will see this post and lead me to a resolution.