The United States Postal Service has issued the following Industry Alert: June 2, 2018 ACS Industry Alert ACS customers please be advised that USPS has identified a discrepancy in the invoices that were produced for the April and May billing cycles. We are requesting that you DO NOT pay the invoices for either month at this time. The National Customer Support Center is reviewing the ACS billing process to determine if any adjustments to assessed charges are required. After completing this review, any refunds or credit to customer accounts will be made as necessary and new invoices will be issued to all ACS customers covering the April and May billing cycles. We will update you upon finalization of our analysis. Please contact the NCSC at 877-640-0724 (Option 1) or by email at acs@usps.gov with any questions.