Postnet has compromised my work due to nigligence

I was commissioned to do an art work (portrait) by a client in JHB Kempton Park which I framed at a local upmarket place in East London. I decided to utilise Postnet on 02 December 2015 for n overnight delivery. Yesterday I called the client as I have not heard from him. He told me that the parcel is still not delivered to his home. I called Postnet in East London, Vincent (where I sent the parcel from) to track the art work, my contact details were taken and no one returned my call within the promised time. After 2 hours I called again, to b told that they're busy 2ndly I learnt that the parcel was not delivered and the glass on the frame was shattered. I was asked to call the client to request whether he would wish to receive the parcel as is and if I know of any framing companies in JHB and whether I wrapped the parcel...(they wrapped it with bubble wrap with \fragile"stickers all over). No apology issued except \""We will take it up...\"". I demanded the art work be returned to EL"