Package with missing/ ****** items

I have been ordering from China for the past 4 years without hastles, but recently that changed the South African Courier service to this company. In February I received an order with 2 missing items. A few weeks ago I received another package with 3 missing items the package had sellotape on not its original seal. When I lay a complaint with them, they always say they don't open packages I must enquire with the merchant from China. They don't even bother to investigate. A very bad courier service