The definition does the heavy lifting. Ours is an enquiry from a person who asked to be contacted about a home loan, with a mobile verified by SMS, checked for duplicates against records already sent to you, and screened on finance before delivery. A record that fails any of those is not a lead and is not billed.
The price is fixed before the campaign starts, and there is no retainer and no lock in. If a lead turns out to be wrong, flag it: the invalid lead replacement review runs within five business days, and confirmed invalid leads are replaced or credited. What the model covers and where it does not fit is set out on the page about pay per lead in Australia.