Does the invoice provide a contact for questions and mitigation/refund/waiver requests?

Sequence no
18
Slug
dispute-contact
Question
Does the invoice provide a contact for questions and mitigation/refund/waiver requests?
Required element
Email, telephone, or other appropriate contact information.
Provision slug
cfr-541-6-d
Consequence if missing
Missing required information removes the billed party’s obligation to pay the applicable charge under §541.5.

Source