You have 2 major issues here. The issue of work contact is one issue; the other, and more severe, is disclosing the existence of a debt to your coworkers.
If you are in Alberta, this collection breach can be addressed with this on-line form:
http://www.servicealberta.gov.ab.ca/1006.cfm
Your privacy issue can be raised here as well:
http://www.oipc.ab.ca/pages/home/default.aspx - You will need to call them about the complaint process.
Bottom line the message you got, totally uncalled for. Your province is tough on collection agencies.
Keep your proof you will need it. This should also offer some bargaining power with the original creditor, I would try to deal with them directly and bring up these unethical collection practices, and provide proof of your complaint, then talk settlement.