Incredibly poor service

I've been contacting them every week regarding my NaTIS documents for my vehicle which I settled over two months ago. They don't even call me back or follow up. I've paid for delivery of my documents, yet I'm still waiting for it. When I call, they either hang up or not answer my call. When I email them, they reply 3 days later with just my tracking number and nothing else. I've contacted DSV and they told me that no driver collected any parcel by them as yet. I don't know what else to do.