It sounds like they have two issues:
* Access to the existing files
* The money given to Google so far
The first you can probably resolve by using the Linux client to download the files to an external hard drive. (edit) And by "Linux client", I probably mean either "nasty perl script that scrapes the web interface" or "some guy charging $5 for a third-party client" or "a Mac that you borrow from a friend".
The second you can resolve 6 months back by issuing chargebacks. It may be polite to request a refund first, after downloading the files.