Adding a dispute, and muting an invoice are done by a very similar process.
From the call console history view
Select the invoice(s) that is disputed (the far right side)
Click the three dots to see the drop down menu
Click add dispute (or mute invoice)
You will then be prompted to add a description of why you taking this action;
Add as much relevant detail as you can.
Decide if you require a response about the dispute then,
Click confirm.
Once the dispute, or mute is added to an invoice it will be shown in the contact history and in the invoice view