Unfortunately, Marriott and Chase have a very strict set of guidelines on how to post points, when to post them, and how many to post.

The deduction of points from your account due to the credit on your CC is actually Chase removing the points, not Marriott. I would just leave this one alone as 16 points isn't worth the time and effort it will take to fix the issue. If the amount was much larger, it might be worth the hours of time you would have to spend on the phone to correct this.