Hi there, our team is distributed around the globe and we may not always be able to answer a question within a 10 or 11hr timeframe. We have different schedules and sometimes it may take a few days. Thanks for your patience! This is a community forum, not a direct channel to technical support.
You can read more about premium search here.
The sandbox free version of the premium search API offers lower request limits per month, and no counts endpoint. It also lack enrichments. See this page for more information.