Tea refers specifically to a beverage made from the leaves of Camellia Sinensis. I won't go into the finery of the etymology of the word, but the word tea comes from the Amoy tê or Cantonese chàh both referring to the camellia sinensis plant. Without this root, we would use some different term to refer to herbal infusions and steeped drinks.
My point is you can't have herbal teas without having actual tea, therefore its logical Randland has tea.
As it applies just as much to just about every word that comes out of their mouth.
Simply put, 99% of all teas I can remember them talking about are very clearly herbal in nature.... But like Yunalesca said, "Tremalking Black" sounds "teaish"... Though even that could easily be an herb...
Sadly I can't really remember any trader talking about selling any "tea", as that would probably be the simplest way to answer the question.... Meh, I think I'd just go with "Yes they have "real" tea, they just don't care about it's "realness" much.", because if they did, then talk of the trade of it, what with how often people drink tea in the books, would of likely been a lot harder to miss.
We only get glimpses into the trade in WoT, but rugs, dyes, gems, steel, grains, silk and tobacco were all overtly mentioned as trade goods. But given that every country, city and town we see in the WoT world drinks tea and no one ever comments on it being a dramatically different drink from region to region implies that there is also a robust trade in teas. The Tremalking Black comment is a clue that there are different (presumably superior) variations, much like Two Rivers Tabac is the best tobacco, but the drink and ritual of tea seem to be ingrained throughout the Western part of Rand land ... I believe the Seanchan drink something closer to coffee.