Unetical behavior from Amarex Couriers!!

One of my suppliers uses Aramex to send laptop parts to me from Bryanston. These gets delivered at Vorster and Steyn Attorneys offices with Michelle at reception. I got all the packages that she signed for so far, except for one. When I queried this with Aramex they sent me a proof of delivery signed by their driver. I still do not have the package and they refuse to compensate me.