Your invoices are in the app: per gig, or consolidated into a statement if your agency bills you periodically. You can view and download each one.
You pay the agency, not GigSpace. GigSpace never holds or moves money. The invoices you see are a record of what the agency says you owe.
Payment terms, VAT and any deposit are the agency's, not ours. Where your agency has set payment terms they'll be shown on the invoice.
If something looks wrong on an invoice, raise it with the agency; they can adjust, void or credit it. GigSpace can't change an agency's invoice.