Maybe need this correction

[tolesolo]

// Take over the rendering of the checkout complete page. drupalgap.menu_links['checkout/complete/%'].pageshow = 'my_premium_checkout_complete_pageshow';

In your custom module of completion page, there is function to call my_premium_checkout_complete_pageshow , but I didn't find my_premium_checkout_complete_pageshow function

maybe it is my_module_checkout_complete_pageshow instead of my_premium_checkout_complete_pageshow