I need a website "switching off"

I've had a website developed but am not ready to go live yet, but the site is live and generating enquiries. I need it switching off or "under construction" or losing the contact details or just hiding it until I'm ready to go live. I can't trace the guy who built it for me. I've no idea what it entails. I will be needing other "web" help such as landing pages etc for another business and just need someone who can dso this stuff without blinding me with science. I don't speak the language!