You can try with some tools from OnTrack like the Easy Recovery
There are many software based recovery tools available. I have used R-Studio and others for bad/corrupt disk recovery. I like ones that make an image of the disk first, use that for the recovery and restore to a separate location preserving the media (then you can still use a third party hardware recovery service if necessary). You need a large workspace and lots of time depending on the size of your disk,
In your case, it will be very difficult to recover information. From the description of what happened, my guess is that only part of the information was written. So you have file fragments and a partially corrupt file table. A disk editor can look at the bits, but unless they are text based files there may not be much there to recover. If you are capable of determining file type from the file header and then editing the bits you may can save some of the information (I don’t get into that level of work).
As to cleaning up the fragments, use a command prompt to delete the corrupt entries after you have attempted to recover the information. A checkdisk may be required first to repair the file allocation tables. Worst case, copy everything off that you can and reformat.
A better choice on USB drives is to reboot the system if the process can’t be killed when a file copy hangs. You will still get fragments but there is less of a chance of corrupting the the entire file table on the drive and losing existing information.