That is sad. I found the following note in their faq:
UPGRADE LICENCE from MSN/Yahoo! version to ICQ/AOL/MSN/Yahoo!
You may upgrade current MSN/Yahoo! IM+ version to ICQ/AOL/MSN/Yahoo! version.
You may do this on the page devoted to your version:
Please note that current licence is for registered users of MSN/Yahoo! versions.
Did you try the registration number that Handango supplies with the free purchase?