Lost Canvasses of Autistic boy

I have a 13year old Autistic boy that is a incredible artist, he creates the most beautiful artwork & I get it printed for him on canvas or poster & I help him sell it. Between the 29th of November & 2nd of December, canvases went send to various clients through the Courier guy. To my absolute shock I have learned over the last few days not only were some delivered to the wrong address, but 2 A0 Angelo cotton mounted canvasses is missing. When I enquired, I was told it left Durban on the 2nd of December, 2 weeks ago & photos were sent to me, with items that's not our canvases. In the meantime we had to carry the financial burden of getting these canvases redone & resend. The manager at Durban depo, treated us like we were at fault, when clearly as I've send him all my correspondence with the depo I've communicated with. Two weeks later still my sons artwork is missing, very unique, valuable art & as a very small mom & son business, we had a massive loss of income due to these people. I asked about compensation & was told nothing will be done about our situation until the investigation is completed & it can take weeks. In the meantime we have to find a way to recover from a tremendous financial loss due to this company