Maintain register for customer invo

Maintain register for customer invoice;
Review customer invoice to ensure accuracy. Also, prepare other customer invoice except from gas revenue, such as penalty charge, etc.
Prepare related journal entries and supporting document, e.g. AR invoice voucher.
Maintain register for collected transaction;
Monitor and verify customer payment transaction, including follow up overdue receivable.
Prepare receipt, tax invoice (if any),
Prepare related journal entries and supporting document, e.g. sale receipt voucher.
Calculate, register, and prepare supporting document related to penalty charge transaction in case of late payment.
Prepare customer related report, such as aging report, overdue A/R report, etc.
Prepare Output VAT report.