Calling with threat to contact me through my human resources department to pursue collection or serve me at my home.

Tell them to do it properly-meaning to send you everything via the USPS with return recipt

They have my address and the last 4 of my social

Received the same call reporting that a claim had been filed against me and that it would be pursued at either my residence or work.

Here is the exact message;
"This message is intended for NAME HERE. I am contacting you from the processing division. I received an order for you; it looks like two charges pending. Now unfortunately because I have been unable to reach you by phone, I will be actively pursuing you at your place of employment and residence. You have the rights to contact the clients to resolve this matter voluntarily, understand, when you are located you have forfeited that right. Your case number is ######. You can reach the office at 660-530-0029."
1)    The process division of what?
2)    Who are the clients that have “placed a charge”?
3)    What type of plum fool do I look like calling them and giving them ANY type of information?