Now, I'm being told that the Upgrade to Windows 7 is "no longer available!"
Shesh!
If it’s the MS Website saying it’s not available, then I would try sending some furious emails to the customer service of MS and the computer manufacturer. You paid for a product, and they now refuse to deliver. Put the onus on them to find a way to deliver that product to you. Make a few veiled threats that you will publish your story on a techblog and call a lawyer, and I will bet they get you W7, somehow, free of charge.