Collection agencies are NOT allowed to call anyone's place of work EVER unless they have received prior written consent to do so. He could be in deep sh*t for that alone. As well, anyone saying they will send you to a "legal department" unless they have the authority, permission and the intention to sue, it is illegal to make that threat. And even saying they have a "legal department" is misrepresentation and classifies as extortion to mislead. And if that IS the case, you have every right to ask for the name of the investigating officer and the case number. If they cant provide it, then they are full of sh*t, and you can sue them for extortion.