Thanks for the compliments on the extension. We definitely work hard on it, and glad your happy with your subscription!
As for your issue, you're going to love the reason why it's not working... we never implemented a JFBCRecommendations tag.

However, there's a super-simple way to do this yourself in an article:
1) Create a new JFBCRecommendation module. Configure the parameters (on the right) how you want
2) Assign the module to the "jfbcrecommendations" position (you'll have to type this in, it won't be in the drop-down)
3) In your article use the following:
{loadposition jfbcrecommendations}
That uses the Content - Load Module plugin (distributed with Joomla) to let you insert the recommendations module in content. A few extra steps over our own tag, but hopefully not too inconvenient. If it doesn't work immediately, make sure the Load Module plugin is enabled.
Hope this helps! If you have any other questions, or run into issues, let us know!