Theft by their staff

I flew from Jnb to CPT when I landed my bag was broken into. Items taken and the staff members told me that I should make a police report. I did all that and got them qoutes of the items taken from my bag. The staff member tells me mango will not pay me the loss I have incurred due to their neglect they will only pay R145 per kilogram. My sneakers cost R3k and weigh less than 200 grams not only that two pairs taken and two jeans and a perfume. Mango is aware of this issue why are they not keeping their customers safe including their goods.