Onepage Checkout SaveBilling observer - Customer email is required

[jfcromp]

I'm trying to create an observer after the customer saves his billing address (onepage checkout). What the observer does is validate if a giftcard matches the customer email address (external service). Everything works fine, but order won't process at the end. I always get the erro "Customer email is required".

Anyone can help? Here's a quick view of my code:

config.xml

<controller_action_postdispatch_checkout_onepage_saveBilling>
          <observers>
              <community>
                  <type>singleton</type>
                  <class>community/observer</class>
                  <method>afterBillingMethod</method>
              </community>
          </observers>
      </controller_action_postdispatch_checkout_onepage_saveBilling>

the actual observer (simplify version)

public function afterBillingMethod($observer){

    // Get quote
    $session = Mage::getSingleton('checkout/session');
    $quote = $session->getQuote();
    $coupon_code = $quote->getCouponCode();

    // Get customer billing email address
    $post= Mage::app()->getRequest()->getPost();
    $email= $post['billing']['email'];
        if($coupon['email'] != $email)
        {
          $rule = Mage::getModel('salesrule/rule')->load($coupon['rule_id']);
          if($rule)
          {
            $coupon->delete();
            $rule->delete();
          }
        }

    return $this;
  }

[theMageComp]

@jfcromp

First of all check if all the inforamtion are being receiving in observer by debugging your code with Try and Catch.