That's a bummer. Table top drives are always a worry . Epsecially the "desktop" style drives. They're much less tolerant of impacts than notebook style drives. I worry about even having "thunks" on a table where a desktop style drive is operating, especially if it is actively reading or writing.
Since you seem to be willing to pay for a clean room data recovery on this (if necessary), it is critical that you not do further damage.
You described the drive being yanked off the table while it was operating. It is reasonable to assume that there is mechanical damage inside the drive. You should not power up the drive unless absolutely necessary (or at all), because it could result in further damage. Imagine that the heads may be scraping across the platters, and that powering up the drive causes them to move back and forth, doing more damage. Or, there is debris in the drive and it is circulating.
As others suggest, there could be a usb connector issue, or other electrical problems. It is fine to work those issues, but do not do it with the drive connected. You would need to remove the drive and then diagnose whether the drive power connector gets power, etc. But even if you fix those issues, I don't think you should risk powering the drive up.
Very few companies are qualified to do a recovery where the drive must be opened up. They'll just be sending your drive off to someone who can. So don't bother with intermediaries.
A proper recovery place, with the skills and available hardware, may remove your platters and install them into an identical model drive. OnTrack is an old brand in the business, but I don't have any specifics recs.
Good luck!