Hello there!
On the one hand I am very happy that the plugin works for you, but I would love to know what the problem with GoDaddy was, so that I can predict it in the future.
Here is most probably why you only see τηε 640 folder: the plugin takes into account the biggest of the two dimensions of each device. So if you check your website from a device with dimensions 480×640, for instance, then only the 640 folder will be created, because the plugin does not know whether the user is looking the website at the portrait or landscape orientation.
However you are right, the images from the NextGenGallery are not being resized. Does the NextGenGallery put something on its own in the .htaccess file perhaps? Somtehing that overrides my own settings?