Unable to remove old CSEvent

I have a CSEvent which I am unable to get rid - nor can I overwrite it with new data.

JS

(function(){
    'use strict';
    var csInterface = new CSInterface();
    var event = new CSEvent("com.adobe.PhotoshopRegisterEvent", "APPLICATION");
    event.extensionId = "com.example.psevents"; // Optional param
    event.data = "1936483188"; // charIDToTypeID("slct") - which is "select"
    csInterface.dispatchEvent(event);
    function init(){
    // code
    }
    // Handler for the event listener. Fires off when a layer is selected
    function PSCallback(csEvent){
        alert("callback triggered");
    }
    init();
    csInterface.addEventListener("PhotoshopCallback", PSCallback);
}());

I've tried

new CSEvent("com.adobe.PhotoshopUnRegisterEvent", "APPLICATION");
...and dispatching it, as well as using

csInterface.removeEventListener("PhotoshopCallback", PSCallback);

I am unable to remove (unregister) it completely, but once I register it again and try and add new data to this, say

event.data = "1668247673, 1885434740, 1668641824"; // copy, paste, cut

...the old event.data just comes back and the callback fires off on selections.

What's the proper way of removing old CSEvents and/or overwriting them with new data so they fire off on something else. This is getting very frustrating!