When do Packnet create and send out invoices?

You will receive your invoice for monthly services on the 1st of every month. 

Monthly billed services include extensions, trunks, numbers, call recording, call storage, connectivity and fixed lines. 

Services billed at the point of the order include hardware items, such as IP phones or routers, and invoices are created on completion of the order. Porting charges are billed once the port has been completed.

How do I know what is billed in advance and in arrears?

All billing is based on the Product billing definitions.