[itsprofitbaron]

You should change the domain name you are operating from.

Also I'd stop redirecting everyone to AppointmentReminder.co & having users login at ReminderBookHQ.com for one thing, its bad user experience and its not great for SEO.

Sure you can claim that you have an EMD (Exact-Match Domain) but it doesn't really help SEO, in fact Google recently released an update to tackle EMDs even further. Likewise, it doesn't help you have rivals with the same name on a different tld - patio11 - appointmentreminder.org

You should definitely stick to one domain name and preferably change it, unless you can acquire ReminderBook.com. The reason for this is that its extremely beneficial for you to own the .com as you're targeting users who aren't exactly web savvy. Likewise running everything from one domain would be more beneficial to you in terms of User Experience, Branding & SEO amongst other things as well.