Hi @sean_winter ,
Welcome to the Community.
Regrettably, at this time, Klaviyo does not offer an integration with Calendly. You could make use of the Zapier service to link it to Klaviyo, however, we wouldn't be able to assist with that. Once you are successful in having events reporting to your Klaviyo account, we'd be able to review the Flow you've built to troubleshoot any dynamic data issue.
In case you need it, here is the link to our API docs: https://help.klaviyo.com/hc/en-us/articles/115005081367-Klaviyo-s-API-References