JustDial.com — Cheating by a number registered at your site

I got a dig dealer number [protected] by the name Home delivery dog kennel.. They promised delivery of puppy and asked me to transfer 500 as token money. I Paid it and they are now not responding to call and messages.. Seems like they extract money by wrong means.. they might be doing this with so many people.. How do you ensure that this doesn't happen through your website.