Hi k-la,
Relax The Back doesn’t sell any latex mattresses as far as I know (and as you mentioned none are listed on their site). It’s possible the post you read was referring to Healthy Back which carries a line of Talalay latex mattresses.
Some of the better options in and around the Atlanta area I’m aware of including quite a few that make or sell latex mattresses are listed in post #2 here.
Hopefully you’ve also read post #1 here which has all the basic information, steps, and guidelines that can help you make the best possible choices … and hopefully keep you from walking through the front door of any of the chain stores 
Phoenix