Please try unmounting your device with the "umount" command in the terminal. You will need to type "umount /dev/XXX", replacing /dev/XXX with the actual path to the device.
Then try remounting with "mount /dev/XXX /path/to/mountpoint -o rw,users", once again replacing /dev/XXX, and replacing /path/to/mountpoint with the location that you want to mount your device to.
The "-o rw,users" part of the second command tells your computer to let the device be writable, and to let users access it. Good luck
Also FYI, you will get help easier in the future if you put a descriptive subject title for your post.