Payment for what?

I have ordered 6 shipments from China. I have paid all delivery and import taxes to an external Buffalo courier. Now on my 7th delivery Aramex is asking for additional shipping charges but won't clarify what they are for. I have not heard anything back from Ntombifuthi Ntombela nor Aramex inquires the last week and apparently tomorrow is the lady day I am given to pay. SUCH BULL****. WHAT AM I PATING FOR AND WHY ARE THERE TWO IMPORT TAXES ALL OF A SUDDEN?