Can't retrieve credit card expiration date from customer

I'm trying to display an alert when a case is started that lets the support rep know if their credit card is expired.  But while trying to retrieve the credit card expiration date, all I get back is 'undefined'.  Any ideas?

function caseInit(fieldType, fieldName)  {    var customerRef = nlapiGetFieldValue('company');     if(customerRef != null &amp;&amp; customerRef != undefined &amp;&amp; customerRef != "")   {    var record = nlapiLoadRecord('customer', customerRef);    var numberOfCreditCards = record.getLineItemCount('creditcards');        for(var x = 1; numberOfCreditCards != null &amp;&amp; x &amp;lt; numberOfCreditCards; x++)    {     <span style="color:'"Red"'">var ccExpireDate = record.getLineItemValue('creditcards', 'ccexpiredate', x);</span>     var today = new Date();       if(ccExpireDate &amp;lt; today)     {      alert('Credit Card is Expired!  Expired on ' + ccExpireDate);     }    }      if(numberOfCreditCards == 0)    {     alert('No Credit Card on File!');    }      else    {     nlapiSetFieldValue('custevent43', 'T');    }   }  }