Postnet Cresta

Asked to do an overnight delivery for me and my parcel didnt get delivered. They couldnt even track where it is! So got the parcel back on Tuesday and since then I have been waiting for the manager who apparently is the ONLY person who can authorise my refund to authorise it. Its now the end of Thursday and I'm still running after the manager to give me my refund. I keep getting told "she will come in tomorrow" and when the tomorrow comes I get told tomorrow again. I don't know when the tomorrow will come or if it will ever come!