Q: This update is not available for this Apple ID either because it was bought by a different user or the item was refunded or cancelled.

If you have not done anything else to your system such as changing hardware or upgrading computer or other software, contact Apple:

iTunes Customer Service Contact - http://www.apple.com/support/itunes/contact.html > Get iTunes support via Express Lane > iTunes > iTunes Store

Contacting Apple for support and service - http://support.apple.com/kb/HE57 - select country

You might also wish to wait a couple of hours and see if the problem persists. In this day and age where items are so complex I could see the servers not talking to each other correctly.