Creditor calling me about someone else in my work place

What are the legalities surrounding creditors (specifically Partners in Credit) calling my workplace on a day to day basis about someone that works in my office? I've given him the messages and asked them to stop calling, but they are rude to me and...

continue to call.

Ask to speak directly to their supervisor (don't deal with the person on the phone - take it higher) and tell that supervisor they are *not* to call the workplace anymore - it could affect the person's employment.

They are not allowed to harrass anyone at work, but they try, nonetheless.

Refer them to your manager. If they persist, contact the Attorney generals Office and file a complaint.
They;ll listen!