Buffalo *****s our package and they don't take accountability

I ordered from shien ,paid my customs ,now I recieve an email saying that my parcel was lost in transit ..they are only going to refund me the money but not the one I paid for customs..why are you making your problem mine ,why ist that I have to my money and you guys are not taking accountability...I need to reaburse all the money I spent including the one I paid for customs