Disabling Suscriptions through WP.com

I have an AWeber subscription web form on my self-hosted WP.org blog that is working properly. However, people are finding my blog through WordPress.com and subscribing through a back way. Is there a way I can disable this action to force people to use my web form? Or do I need to contact them via email and ask them to resubscribe using the web form? Thanks.

My blog is http://www.energymanagementinsider.com .