For details about the invoicing, please see detail as below.
1. In case of invoice , we can't delete the invoice in the system for create new invoice.
2. Cases are amend invoice , only we can issue extra invoice or issue credit note sent agent.
3. Because rules info from Eric in order not to delete the invoice in the system.
4. So you can bring the invoice and Elrond sent agents to refer to payments in the latest prices.