(Added after writing the text bellow: I finally discovered what was wrong and it was a 3rd party plugin for calculating shipping. I changed the rating like I said. I still think you could had easily avoid most of this if you really cared about your users by simply testing the first update you did which was a disgrace to every single site and it had nothing to do with 3rd party plugins or themes. Anyway, I wish you the best because this really is a great plugin)
Just because this is a free plugin it doesn't mean you have the right to trash everyone's sites like this! This was a completely irresponsible move of you guys! I'm sure you knew this update was going to do this, and if you didn't then you just didn't care enough for all these "ungrateful fools" since all you had to do was test it in a single site to see it doesn't work as it should.
Fix this and I'll change my rate.