The domain name RF.com looks to have changed ownership over the last couple weeks. The two letter.com was owned by RingFree Mobility. According to Venture Beat, RingFree Mobility Inc. is a mobile communications software platform enabling Voice over Internet (VoIP) services to easily expand calling capabilities to mobile devices. The company was founded in January of 2008, calling the number associated with the company today, that number has been disconnected.
Here is a screenshot of the RF.com website from May 18, 2013 courtesy of archive.org:
November 19, 2013 changed to a Go Daddy holding page
On January 23, 2015, Joe Uddeme tweeted that Domain Holdings was the exclusive broker for the domain.
— Joe Uddeme (@juddeme) January 23, 2015
On 4/15/15 the whois changed to a HE QINGHUA out of FUJIAN, China.