Unfortunately, the price we have pitched the plugin at does not allow us to help you with any general printing issues. The plugin is a connector between Google Cloud Print and your WordPress site, and we are only specifically able to support that aspect. (To use an analogy, if you buy new tyres for your car, then you’ll understand that the tyre supplier’s service will not include investigating engine issues). To use this plugin, you need to ensure that your printer, any device driving the printer, network and connection to Google Cloud Print are all working, as pre-requisites.
If you want to test that you can manage connecting to Google Cloud Print before you purchase the plugin, then you can use the free Google Cloud Print WordPress plugin to help you.