This is the company that imports Tetley's into the USA and then distribute it.
http://www.rjdistributing.net/contact-us
Call them and ask them where you can buy it at in DFW.
If they are doing their job, they should know which retailers in which state, county, city has their product.
I once called Barilla and also Tyson to see what stores in DFW had one of their particular product and they were able to tell me
Heck I called those stores myself afterward and even the grocery and meat managers at those stores didn't even know they had those 2 items that I was looking for on their shelves and in their freezers.