Magnetic Umbrella Clamp

I bought the clamp instead of the magnetic base and boy am I disappointed! The clamp does not attach to either the umbrella or the umbrella extension (which is also a big disappointment.) The clamp has a 3/8" threaded rod nut on it which one would assume connects to the umbrella or the extension with a threaded connection. However neither has a threaded connection. To use the umbrella, I have had to purchase a piece of threaded rod which threads into the clamp and then I shove the other end of the threaded rod up into the umbrella shaft. As far as the extension goes, it's approximately 12" long and doesn't connect to the clamp. I assume it was designed to work with the magnetic base, but since I didn't buy the base I took a leap of faith when I bought it. Frankly, I was expecting a longer extension but since there is very little information in terms of description of these products, I bought them sight unseen. Shame shame shame!