The answer depends on whether or not the dispute has escalated. Simple, or regular disputes are mutually solved by the parties.
The buyer and seller set the new deadline for the delivery and clearly define what must be delivered and what is not allowed. For a case to remain anonymous and fair, communication is done via a Contract Chat. It will also provide the necessary details for the Agent if the dispute escalates and neither party accepts claims or new terms.
You can learn more about the dispute escalation process from other questions and answers in this section, or visit User Documentation.