You can always stop selling the virtual/in-person events after certain time period by following the steps given below.
Go to Events page in Servv and look for the event you want to stop the registrations. Click on "View product details" option for that event. The product page will open.
In the inventory section on the product page, select the option "Track quantity". Make sure you uncheck the option "Continue selling when out of stock". Enter the value "0" in the Quantity field. Save the changes.
Go to your online store and browse the event. The event will be marked as "sold out".