I would agree that business is done by mutual consent. The key word is "consent " also known as agreement of the parties.

What you "normally" do and that to which you actually agree may be two completely different matters. I am having difficulty understanding why timely payment is an issue. It has been my experience that inability to make timely payment suggests undercapitalization of a company. Your company should have sufficient cash reserves to pay its vendors without having to wait for payment fom your client.