FYI, if you haven’t already found it.. on the summary page where it shows your earnings to date, earnings paid to date, rpp, income, etc as summary… if you click on the link to the left of the revenue amount there, it’ll pop-up a new window with 90-Day stats. I find that the most useful. It shows day by day the Netwin, Loyalty, Promos, and also has chargebacks. You should be able to get an idea what happened by viewing your Netwin the last days and then scroll down the same window and look at the promos and check for chargebacks at the bottom.
Maybe you already knew of the 90-day stats, in case you didn’t now you do. 