How to setup Notification URL to change order Stat

-- HikaShop version -- : 2.4.0
-- Joomla version -- : 3.4.1
-- Browser(s) name and version -- : Chrome

Hi Admin
I use Voguepay payment processor plugin & I want to setup the plugin to automatically change order status to confirmed after payments. Payments can be made with the plugin but hikashop isn't notified automatically and order status still says created instead of confirmed that is, The orders status still says created after orders has been paid for. Also , for failed & cancelled transactions, it still gives a thank you message. My questions are, In the settings of the plugin, what do I fill in the
1) Notification URL
2) Success URL(URL to redirect when payment is successful)
3) Failure URL (URL to redirect when payment fails)
I left those fields empty because i dont know the Url to fill in there and used the automatic setting and I guess that's the reason why I'm not notified. I will like the success URl to redirect to orders page with the thank you message it usually pops up & failure URL to redirect to a failure page or orders page with the option to reorder & pay for it again(checkout) and failure message pop up. How can I customize the thank you or failure message displayed to add my own text/message

Thanks

Hi Nicolas
Unpublishing the hikashop payment notification plugin like you suggested solved the issue of changing the order status to Confirmed.Thanks for the help
But there's another problem, it redirects to me to the URL www.mywebsite.com/index.php?option=com_h...after_end&order_id=5
With a thank you pop up. I will like it to redirect back to the customers order page after successful payment & to redirect back to cart for failed orders.
2) How do I customize the thank you message displayed to add my own text
Thanks