Note: this is for further discussion of the answer given here: http://www.libreoffice.org/get-help/frequently-asked-questions/#donate
Firstly, The Document Foundation says thank you for your donation! It is very much appreciated. Donations are purely optional, and you can always download LibreOffice for free. From the download page – http://www.libreoffice.org/download/download/ – after clicking the “Download” button you will see a link on the following page, above the donation message, like this: http://www.libreoffice.org/assets/Uploads/libreoffice-download-link.png
Just click the link to begin downloading LibreOffice. If you still have problems, please check that your browser, operating system or security software isn’t preventing the download from taking place. You can also contact download@libreoffice.org with your operating system version, and get a direct link.