aMember (site.php): How to redirect user to custom landing page once he cancel his subscription

site.php

<?php

Am_Di::getInstance()->front->registerPlugin(new class extends Zend_Controller_Plugin_Abstract {
    public function preDispatch(Zend_Controller_Request_Abstract $request)
    {
        if ($request->getModuleName() == 'default' &&
            $request->getControllerName() == 'member' &&
            $request->getActionName() == 'payment-history') {

            $di = Am_DI::getInstance();

            if ($invoice = $di->invoiceTable->findFirstBy(array(
                'tm_cancelled' => ">" . sqlTime("-5 minute")
                ))) {

                if (!$invoice->data()->get('redirect_done')) {
                    $invoice->data()->set('redirect_done', 1);
                    $invoice->save();

                    $request->setDispatched(true);
                    $this->getResponse()->setRedirect('/cancel.php');
                }
            }
        }
    }
});