WHMCS Bridge is the only plug-in I found and works perfectly as it says on the box. Since I started using it I had great response from the support team and they even made my WISHES come true by adding a new function to the plug-in. Highly recommended, it is easy to install and get it running even you have no knowledge of coding. Simply use the presets on Plug-in settings.
A big thank you to ZINGIRI, providers of this plug-in.