Talks at Google - Chris Voss
No is not the end of a negotiation, it is probably the beggining. After saying “no” the other party is feeling secure and might now pay more attention to what you have to offer so they are now easier to persuade.
Start a cold conversation with - “Is it a bad time to talk?”
Ensure that the other party feels completely understood by you. So be clear on what you think they are saying and why.