There's a typo in the shortcode, should be (add the "u"): [link_obfuscate_telephone tel="???"] I don't understand how to use the additional features but this solved my problem of phone numbers not being clickable on mobile. In some places my theme overwrites the typical blue clickable mobile numbers with black. I am trying to use Mobile_css_class to force it back to blue but I can't figure out how to do it.

Works perfectly. Thanks for this plugin!