There's nothing to worry about with that warning.

All new sign ups are on the basic plan which is free and you can add up to 100+ patients to give you amply time to give the app a try BUT we also give access to 30 days of unlimited patients and storage because some doctors would want to import thousands of patients profiles right off the bat within their first week. 

If you see that warning, it's just saying that the 30 days of unlimited access is coming to an end.