If you want to show any custom message to user, on subscription
completion. You need not to change the core code and not to over-ride
the template. You just need t crate a instance of Content App.
Follow
the below steps :
Go To App screen of Payplans in admin panel
Click on New button on top right corner.
In pop up window Select App Type "Content"
Fill
the basic details and in Parameter section there is a field apply page
on. Select the value "Order complete and successful"
Select the
position where you want to display the Thank You message. You can write
content yourself or can attach an existing Joomla Article.
