Tampered Parcel

A parcel was sent to us from Postnet Karaglen Edenvale, to their Postnet branch in Howick ,upon receiving our parcel we discovered that the type of tape that was used to seal the container was tampered with and a different type of tape was used to seal off the container, upon further investigation when we opened the container , we found one of the items missing that was supposed to be there. We have tried to get hold of the Postnet Karaglen branch to find out what's going on , but no success due to their website saying they're "temporarily closed" , which is very strange and got us thinking why now all of a sudden ? Its been over a month since we tried to get hold of Postnet Karaglen branch,as well as other avenues,including aramex,to clarify on what's going on , but all fingers are pointing to Postnet Karaglen. I want to ask you Postnet Karaglen , how do you explain to your child that the present her uncle sent to her via post/courier , didn't arrive because it went missing/got ****** in the transporting process??? Please answer me that question, I will not make use of Postnet (karaglen) ever again due to poor customer service