Very sorry to hear you are experiencing issues with the plugin. Just to clarify a bit, are you seeing this issue in WP-Client LITE, or WP-Client Pro? Which version number of WP-Client were you running when you experienced this issue? Additionally, what version number of WordPress?
When you say that the shortcodes do not work, do you mean that they are simply not displaying any content in the frontend, or are you possibly receiving any kind of error messages when logged in as a client? This is obviously a core functionality of the plugin, so we would like to get this resolved for you as soon as possible.