Horrible experience. Tried calling to locate a st...

Horrible experience. Tried calling to locate a staff who doesn't know how to reply emails and calls since Jan over outstanding invoice.
Operator at mainline, unhelpful, transfer call, when called back to say no respond, won't assist any further when I asked for the dept head and just transferred me to another number. Lady was equally secretive, refuse to disclose name nor department and simply said I'll pass the message. Obviously, still no call from the person I was looking for... what's wrong with the staff there?