Unfortunately the topper you purchased isn’t Talalay latex and is probably firmer than you were led to believe as well. I would read this post and this post and this topic (about their polyfoam and sources) and this post (presumably from a past employee) before buying anything from Foam by Mail (AKA FBM and Foam Factory) or considering them as a reliable supplier … especially if the specific properties or firmness level of the foam you are buying is “application critical” and would make a significant difference to you.
The better options or possibilities I’m aware of in the Houston area are listed in post #2 here but I don’t know if any of them would carry a topper that meets your criteria so you may need to make a few phone calls to check.
Post #2 here and the topper guidelines it links to also includes more information about choosing a topper that can help you use your sleeping experience as a reference point and guideline to choose the type, thickness, and firmness for a topper that has the best chance of success and also links to the better online sources for toppers I’m aware of as well.