Rented a cutlass black and got ripped off at Jumptown

So I saw some yt videos about how to trade ilegal substances in the game, in the videos they said you could make a pretty big profit with a small investment and a small cargo space and it seemed pretty interesting to me so I rented a cutlass black and flew to jumptown. I had never been there before so It took me some time to find it but when I finally landed there I went inside to look for the trade terminal but it wasnt there? It was just as if it had vanished? I looked up some videos to see where it could be and I went to the exact place where I should see it but it just isnt there. Could someone please explain im so confused hahah.