2025-07-23 00:00:00 Application for ONCE employees. Download the app and you can manage your payroll, request advance payments, modify your tax or banking information, access promotions, offers and news, etc. Customer service for sellers, telephone ARCO 911253411. For non-seller workers, telephone number of the ONCE User Service Center (CAU) 911511906. ARCO's hours are 24 hours a day, and CAU's hours are Monday to Friday from 7:00 a.m. 45 to 11:00 p.m., and on Saturday and Sunday from 5:30 p.m. to 10:00 p.m.