How do I download my upgrade when Apple Store choices are wrong?

Question

I'm running Snow Leopard, and bought the Mountain Lion upgrade.  I received an email receipt from Apple with numbers and links.  I don't have the App Store app.
When I go to the app store the only choice is to upgrade to Mavericks.  I don't want Mavericks. I bought Mountain Lion, but don't see any way to download it.  In 20 years on computers, this is the dumbest upgrading experience I have ever had with any software, much less an operating system.  They could hardly make this process more convoluted and obtuse.
When I went to the 'contact Apple' page, they ask what OS I'm running, but only give two choices, Lion, or Mountain Lion, which are both wrong.
Does anyone have the magic beans I need to make the giant fall off the beanstalk so I can download the software I bought?
thanks for any help,
Greg

Answer 1

Ok, after jumping through a series of hoops, I got Mountain Lion istalled.  Here's what happened.
The reason I couldn't find Mountain Lion in the App Store is that it isn't there!  I wrote them via the Help link, but in the end had to call the 800 number.  The support guy used Screen Sharing, which meant he could see my desktop, so if anyone calls support have your Apple ID written down on paper so you don't inadvertently reveal too much information.
Tha App Store has a special section where they keep Mountain Lion.  He led me to that page so I could clearly see the 'Download' button before I ended the support session.
Haivng read about 4-hour download times, I was concerned about tying up my computer during the day when I had computing to do.  I had no way of knowing how busy the Apple site was, but it was mid-day on a weekday, so I figured it would not be too bad. Also, I assumed that most everyone on my Time Warner Cable network would be at work, so I didn't expect too much congestion on my end. 
As it turned out, downloading the 4+ GB file was waaay easier than expected.  At around 1pm Friday I started the download, it took about 28% of my massive 8-core processor and I averaged about 5MB / second.  My ISP connection is what they call 'Standard', the 3rd out of the 5 speeds TWC offers. The entire file was finished downloading in about 30 minutes!  During the download, there's no visible progress bar, and the 'Download' button was not grayed out, so the only way I knew the file was downloading was by the sound of my hard drive working.  To be sure the file was on its way, I opened my Mac's Activity Monitor.
When the download was complete, the installer asked me where I wanted the upgrade to be installed.  I chose an empty partition on my hard drive that I had cleared off for this purpose.  Mountain Lion was quickly installed.
With my partition divided in half, I continue to be able to run Snow Leopard on one half, and Mountain Lion on the other.  On reboot, after the screen turns black, I can hold down the Option key until a screen opens that offers me the choice of which OS I want to boot into. When I bought this Mac Pro in 2010, the first thing I did was partition the hard drive into 2 parts, and reinstall Snow Leopard on one.  For the last three years I've been using the non-boot partition for storage. Running two operating systems like this makes it easy to work on one OS from the other.  Installing DiskWarrior 4.4 on each partition enables me to repair both.  DiskWarrior has saved my butt more times than I can count during the dozen-plus years I've been running Macs.
I ran the install from my Snow Leopard partition, so after it was complete, the Install Mountain Lion application appeared in my Snow Leopard Applications folder.  The support guy told me that the Mountain Lion installer automatically creates a hidden Restore partition, in case I want to reinstall and start from scratch in the future.  Nevertheless, I wanted to save the Mountain Lion installer onto a portable hard drive.  I partitioned a new Seagate USB 3, 1 TB drive so as to have a tiny 5 GB partition as 1st, and the rest of the drive as 2nd. BTW, the first partition on a drive is a bit faster than the second, so if you are creating a boot partition, make it the first one.
When booting to the Mountain Lion partition for the first time, excessive hard drive activity was heard.  After the OS had fully loaded, reading operations went on and on for ten minutes or more, indicating to me that there was some kind of problem.  The Mac being a Unix platform, I figured there was a problem with Permissions.  I opened Disk Utility, and hit Repair Permissions.  This stopped the excessive reading, but it still wasn't exactly 'normal'.  I booted back into Snow Leopard, and surprisingly the excessive hard drive activity was happening there too. (It hadn't been happening before the new install).  I ran diskWarrior 4.4 on the Mountain Lion partition, and sure enough many 'red' error notices were seen.  As DW users know, this indicates serious problems.  After DW rebuilt the ML desktop database, all was well.  The next time I booted into Mountain Lion, no excessive disk activity was heard.  For symmetry's sake, I installed DW on the Mountain Lion partition, and rebuilt the Snow Leopard database.  Now everything is copacetic on both partitions!
Kappy's very clear instructions on how to put a Bootable Backup of the installer on a portable hard drive can be found here:
https://discussions.apple.com/message/24083335?ac_cid=tw123456#24083335
Hope this helps anyone who is upgrading, now or in the future.
Greg
ps. the Apple Support guys are not trained to do anything like what I describe.  Unless you happen to run into an experienced computer user who thinks outside of the box, all you will get from them is advice on standard installations.