Update Case Status - If Customer Message received

Hope someone can help me wrap my head around this. I'm trying to trigger a Case Status change if a Customer interaction (email) is received.

Below is the code written to date:

function afterSubmit(type)
{

// Load the message record
var message = nlapiGetNewRecord();

//load the case record
var caseRecord = nlapiGetNewRecord();
// Get the ID of the activity associated with the message     var activity = message.getFieldValue('activity');  //Get the Case Status of the associated Case     var caseStatus = caseRecord.getFieldValue('status');  if(caseStatus != '4' || caseStatus != '5') { // If there is any activity     if(activity)     {     // If the activity is a case, load the record and change the status.     try     {         var caseRecord = nlapiLoadRecord('supportcase', activity);         caseRecord.setFieldValue('status',20);         nlapiSubmitRecord(caseRecord);     }         // If the activity is not a Case, log a warning message         catch(exec)         {             nlapiLogExecution('DEBUG', 'Warning','Activity Record is not a Case');         }     }     else     {         return false;     } }