Is the recruiter from the company or from a recruitment firm?
If company - please let the hiring manager know about this. This is wrong.
If recruiter is from a recruitment firm - first inform the hiring manager/HR from the company they received offer from, then refuse to pay.
Definitely name these companies and recruiters. You have at least brought this to GV, but imagine if the recruiter is doing the same with other candidates who might be bullied into paying. It took a long time for the recruitment system and fraternity to move out of such practices and we should not be going back into those times.