WD My Passport 0820 USB HFS+ data disk drive partition problem following accidental use of Recovery Assistant
OS X Recovery Disk Assistant v1.0

If you allowed that assistant to complete its work on the wrong disk (with your data) then it's reasonable to assume that hundreds of megabytes of your data were overwritten. However, from your screenshot it appears that the WD My Passport 0820 Media does still contain a VideoUSBPASS1TB volume; so maybe the assistant was unable to proceed with a drive that uses hardware and/or firmware encryption. 

I suggest taking advice from Western Digital …