The flash memory in USB stick drives has been known to simply 'stop working' on occasion.
Sometimes a re-format may revive the drive.
It may help if you provide a bit more information such as;
Brand and size of the USB?
File system format?
Partition scheme of the USB?
Age of the USB? (the memory does wear out after repeated read/write cycles)
That '8.2 GB' size looks a little odd to me. Usually USB sticks are sized 4,8,16,32,64 GB and so on.
Once the stick is formatted with a file system the available size shows up as something slightly less than the stated full size. Is this stick partitioned?