If a product you bought does not show up in "My Products," you probably just need to register a serial number that was mailed to you.
For the PM problem - if you are using a Mac and the message was "Update of Toontrack Product Manager failed! Could not remove the old version of the application." then the issue is usually that the trash folder has wrong owner. To fix that, open Applications > Utilities > Terminal and copy/paste the following command there (the entire line, unmodified):
sudo chown $USER ~/.Trash
Then press enter. It will ask for your computer password, so type it and press enter.
Since you ran the uninstaller at the point when the update had failed, there will be a problem with reinstalling. But copy/paste this command to Terminal:
open "~/Library/Application Support/Toontrack/Product Manager/Update"
That will open a Finder window that contains the Toontrack Product Manager application. Move it to the Applications/Toontrack folder and all should be good. Run it from there.