Unreliable system

My daughter broke her glasses on the first week of January on her first day at school. Fortunately we had an extra pair but she had left them in Australia where she had visited for the Dec holidays, because it was quite urgent I requested that they send them via post using their EXPRESS services which is expected according to them to take 5 working days. The glasses were posted on the 12th of January and sadly to this day I still haven't received them. I have been tracking the parcel on line for the past 3 weeks and the results I get is that they have arrived at the delivery office on the 26th of January. I have been to the Northriding Post office several times and strange enough their system tells them it has been detained at Customs. How can 1 tracking number show 2 different results.. first of all? secondly I've sent an email to the customer care (the email address provided for the public if they cant trace their parcel). It's been a week now I have not received any response. I've tried the numbers that I was provided by the Northriding Post office to call and to no avail. No effort at all by the stuff at Northriding is given to me as we were made to pay extra money for the so called 'express' service, they tell me there is nothing more they can do I need to call the call centre, I've even asked them to use their company phone as it is costly to be kept on hold for over and hour. This is very frustrating now because my daughter can not concentrate well in class, she cant see properly her eyes are strained and its costing us more as we need to get medication to try and ease the strain. As a trusted courier company I must say Post Office has really let me down. And definitely their staff doesn't care about their customers. I've been going there on a daily basis till this day and they still tell me to call them and check for my parcel. They even looked annoyed when they see me walking in. How on earth does one tracking number give different results...Something needs to be done about this. I will never use Post office again.