I WANT MY PARCEL

I have been waiting for a package to be delivered for almost three months now. I have a national tracking number but when I track my parcel it shows it was last scanned at Intl Mailing center on the 29th of September 2018. Even though I was informed by the sender who was also tracking my parcel that it arrived in South Africa mid September, right now that is not my concern. I want to know why it’s been sitting at the mailing center for nearly a month now. I even mailed them my invoices just Incase that is what was holding the package back. Now I get no responses from them.