Incorrect Billing

I was due for upgrade with 1 of my Telkom contract number. Upgrade was done on the 8th of November & traded in my device. To my surprise, the old device I traded in is still showing on my invoice, the trade in amount didn't reduce my account at all as it was suppose to happen. Telkom please explain to me why the trade in amount didn't reduce my account & why am I charged for the device I traded in, how does upgrade work?