I almost had a similar thing happen at the beginning after i answered an ad for escorts on Craigslist...
Over the phone, the guy was very professional, however, he was very vague with his answer when i asked him of his website where i'd be advertised. We arranged a time to meet and he said he'd pick me up from a tube station. I'd made the assumption that we were going to his office or maybe even a pokey little cafe to chat. I was so wrong! He drove to the top of a large multi-story car park and then unzipped his pants! Ugh... I should've bitten his weiner off!

Think he still advertises on there...

Anyway, i decided that that would be  my one and only dealing with an 'agency'! I understood immediately that this was someone just trying to take advantage of newbies and it was not an agency at all but the thought of being in that situation time and time again whilst on the search to find a genuine one was scary.

Moral: Never respond to a Craigslist ad unless you're really bored and able to out-con the scammers for a laugh!