If you have cancelled the default template from the list but this template has been applied on a chart, then save it by tapping on "+" at the top corner of the templates section and give it a similar name as the default template you have erased.
Otherwise if that template has not been even applied on a chart, the only way to retrieve it would be to re-install the mobile application.
The correct way to get rid of a template, is to load another one to replace it. There is also another way: when you have a blank chart without indicators, save that as a template and name it "Blank". So every time you need to clean the chart from all indicators, load the "Blank" template.
This article applies to Trade Interceptor for iPhone, iPad, Android phones, Android tablets, including Kindle Fire and BlackBerry Playbook.