Negotiation is only possible is there are funds in SafePay and one of two things happen:
When in negotiation, communication will continue as normal via the dispute page. It is up to the two parties to decide how to move forward or divide up the funds.
Accessing the dispute page:
Ending a dispute by proposing a resolution:
Your guru is the only one that can resolve a dispute since they disputed your refund request originally. However, you can convey to them a resolution via the dispute page. This is how they would propose the dispute: