They have the same host/ip designated for that domain name which is odd. Either they used you to park their domain or they typoed their DNS servers or they happen to be on the same server that you are on at the same hosting company. Their nameserver url1.buydomains.com shows that ip as the listed IP so that is the right IP that they chose to use. Contact your host with that info and see if they exist on that server with you (assuming shared hosting) and if not, then you can work with the registrar they used to have them pull the domain from your content. The registrar is listed as
www.domaindiscover.com.
Could be just a mistake, but its definately interesting to say the least.