We tested the plugin and working fine with us and other clients without any issue.
The latest version of the plugin works only on Arabic (RTL) sites, so if the plugin didn’t work with you because you have English (LTR) site, this because the plugin affected only on Arabic Language sites which your site language is English not Arabic, so you have 2 options now:
Change site language to Arabic like that > http://jmp.sh/xesarJs
Or use older version from the plugin, You can download the plugin v1.4.5 from here: https://downloads.wordpress.org/plugin/arabic-webfonts.1.4.5.zip
Note: why you don’t use the support system instead of just rate the plugin with 1 star!!