If you have access to your /etc/hosts file you can add
api.plugindata.com 127.0.0.1
or
api.plugindata.com localhost
to route all traffic going to api.plugindata.com to your own machine.
If you don’t have access to the file you can also search in the plugin source code where this domain occurs and either comment the code or maybe use a hook (if available) to prevent communicating.