Also I tried to donate using my Visa card and it would not accept my donation.
First of all, you donot need to donate to download. Each download is completely free. However, a donation is a great help.
I just download the latest still version (I am a bit conservative) for a Mac and it works perfectly fine. I make my download always from: http://www.libreoffice.org/ without a donation.
As for your Visa card and not accepting your donation it is difficult to give you a hand. In general if a Visa card donation is not getting through you must have made little mistake in you process. Repeat if VERY carefull again and make sure the needed scripts and cookies are allowed.
Please also have a look at: There is NO link anywhere in the donations page that lets you go to a download page