Our site is www.orgonoite-brasil.com

We installed responsivizer and configured but are still getting the desktop version instead of mobile version when testing it e.g. on screenify (http://quirktools.com/screenfly/) or website responsive checker.
What are we doing wrong and how can we fix?

That's expected if you use services such as screenfly, etc

They are not services that emulates a real mobile device so obviously they won't return the mobile version. They simply shows the desktop website inside a browser iframe.

Use the integrated device emulator or the Google Chrome emulator in the DevTools.
Take care to have correctly configured the component, the template switcher must be enabled and active, all other extensions managing mobile if any must be turned off, all the caches, cache plugins, plugins such as JCH Optimize, etc must be turned off.

Regards

QUOTE:
all the caches, cache plugins, plugins such as JCH Optimize, etc must be turned off.

You mean just for testing, right?
For us It would be unacceptable to be obligated to turn of all caching for desktop website just to have responsivizer working.

Can you confirm responsivizer is also working with cache and Jchoptimize tools etc., maybe we need to adapt some settings?

Obviously i mean for testing phase. You can use JCH, etc once finished.

You have only to take care of settings of page caching if you want to use it. There is a FAQ for this purpouse: https://storejextensions.org/faq/can-i-use-cache-when-responsivizer-is-installed.html