Extortion?

[Kari1920]

We made a deal when selling our home (due to divorce) to give the buyer some extra cash due to his having to rent his current residence for an additional 6 months following purchase of our home. My husband no longer wants to pay him. There are no documents stating the money is owed. This man has now filed a small claim against us. Does a verbal agreement stand up in court? There is only one witness on his end to this transaction, not in front of us, merely that he explained he would rec'v said amount of money upon our divorce becoming final. This man has stalked us online watching for a court date, has called me numerous times asking when we were going to be getting the final court date, etc. At this point, I no longer want to pay this man either but am not sure I am binding by the verbal agreement to do so. Could his continuing to call be considered extortion?
If we are binding, and the agreement was to pay after the divorce was final, does that part of the agreement stand up?
ANY advice would be helpful at this point.
Thank you for your time.