Only received $207 of my $770 trade-in

Traded in my old MBP for a new MB and the order shows complete. I also show a deposit for $207 in my account however the total refund for the trade-in was supposed to be $770. There was no adjustment to the amount that was communicated and I did not approve a change to the amount. I can not find any other form of payment that was sent to me in any other form.