Parcels going missing

I have an internet based company and use the posting services often but two of my big orders has gone missing it gets excepted at modimolle branch and gets sent to tshwane at tshwane it gets stuck and never gets to were it has to go i track my parcels on [URL Removed] and every time it goes to tshwane it never leaves there. this is coting me a lot of money i have to reprint my orders and resend it via postnet to make sure that my parcel reaches its destination