Lost parcel since 7 February 2019 postnet not assisting

Hi I lost a package which was sent to me via postnet from Queenstown to be delivered at postnet in Worcester. I am deeply saddened by the bad service I am getting as this package was lost in February and until this date I have not been helped. I gave the tracking number then I was informed that the package was lost. They said I can claim for the contents if I provided proof of purchase. I then sent this through and since then I have been calling and my matter is not going anywhere. I’m just being told that the officials at postnet will get back to me. I even have email evidence dating from 7 February 2019 of this matter. Please assist