Didn't you say you threatened them with a Title 18 color of law violation? That's notice of intent.
Also, it isn;t rude to ask who is calling when someone asks for you on your business phone. Its professional, in my humble opinion.
Printed copy · Anthology Volume 3, page 182Printed copy from The Tender For Law Anthology, Volume 3, page 182 (printed 13 June 2014). Added by this site; not part of the Facebook export.