Postnet Centurion Lifestyle management refuse to refund me

I'm selling kitchenware ,so I normally send orders of my customers using Postnet in Lifestyle Centre Centurion as my courier, on the 26 August 2018, 12:19:06 I sent some orders to my two (2) customers, one in Postnet Highveld Mall(Tracking number PPA ********** 5716) and one in Postnet Cape Town Standard Bank (Tracking number PPA ********** 6616). After my customers had collected their orders, they both noticed that the Glass kettle were broken. I then took it up with the management of Centurion Lifestyle in Postnet requesting them to refund me so i can be able to replace my customers orders, but unfortunately at first they told me that the insurance wont pay since they stated that the parcels were not packaged well, i then sent the management the proof of how the parcels where packed and worse i was assisted by one of their employees to park it, after the management saw the proof that i submitted, they then asked me to provide them with the invoice so they can be able to refund me, i then submitted that, now the management comes with other stories that the insurance said they will only pay if i provide them with the invoice of where i bought my staff as they not willing to pay for the price i have given them on the invoice and they also indicated that my parcels were not insured, when i told them that my parcels were insured, they then said each box was covered only for R1000, I then asked them why then they dont pay me because each glass kettle in each box cost R450, Which is R900 that they owe me, why is difficult to refund me, then they change their stories again to say the insurance only pays the cost price so i must provide them with the details of where i got my stock. I ask them to provide me with the insurance document that states that, but they not willing they say all the insurance are working like that. Firstly on the invoice the monies i have spent on fuel driving up and down to their Postnet is not included, the monies i have paid to them to courier those parcels is also not included, So now i have been going up and down to request them to refund me, they are not willing to pay me, they taking advantage of me because i'm a woman. I need my money to paid so i can be able to replace my customers orders. Its been almost a month now and they are not willing to repay me. I need my refund back. So I would be happy if hellopeter can assist me.