Bad Service by Dawn wing

I need help urgently, i had a parcel of mine that was supposed to be delivered to me a while ago, i received my tracking number from the supplier before the 14th of May. When i decided to make a follow-up with Dawn wing as they are the courier company that was used by the supplier i bought from i was told that they can not find my parcel and that they will call me back which they never did. I phoned again and this time i was told that it seems as if they lost my parcel because they can not find it on the floor when i asked what is the way forward and how long its going to take for me to receive my parcel they told me they do not know... I phoned again and spoke to Sean, Dawn Wing Port Elizabeth who was very rude, when i asked him to send me something in writing he said that he was not going to do that and implicate him and the company the parcel is lost, i then asked to speak to Peter Van Wyk who is the branch manager and i was told by Sean that i can not speak to him and that they are not going to put something in writing as they MIGHT find my parcel..