Hi, Christiana. Thanks for your interest in our plugin suite.
We do not handle sales or support via phone or email; support forums are the only method, per our Scope of Support / Terms. (For your privacy, I removed your phone number from your initial message.)
We do not have any integration with FedRamp, but we do have an API: https://theeventscalendar.com/knowledgebase/introduction-events-calendar-rest-api/
Additionally, our plugin suite functions great as a calendar, but it is not designed to operate as a booking/scheduling solution. Our Event Tickets plugin and its Event Tickets Plus add-on could help people register for events.
Last but not least, we have a pretty great Refund Policy so you can buy one or many of our add-ons and thoroughly test them.
I hope this info helps. Let me know if you have any follow-up questions.