This is what is posted at the top of the AMS page:
Billing Data Incorrect in Billing Statements (1/31/17 to 2/14/17)
Billing for campaigns that ran between 1/31/17 to 2/14/17 may be inaccurate. If you are a Vendor, your billing related issues have been resolved and you have received click credits for any excess charges. If you are a Kindle Direct Publishing Author, we have resolved the issue and are processing adjustments to the bills of impacted accounts. These adjustments may take up to 1-2 weeks to process. Your data on impressions, clicks, sales and spend is correct and no information has been lost. We apologize for the inconvenience.
I love the "all of your data is correct except the billing". Anyone interested in buying some swampland?