it's inconceivable to me that you would deliberately obfuscate not only how to contact your company, but how to implement or change payment methods, with or without an account.
if you give a free account, you better have a link in their somewhere for people to contact the department you say they have to contact for payment.
if you say people can change, up or down, payment schedules, you better have that set up in the invoicing section.
not doing so teeters on fraud…