(Back to the jungle, next post in a few days!)
I took off my backpack and threw it into the back of the taxi. Telling the driver I wanted to go to the bus station, I was propelled backwards as the taxi lurched forward. Fifteen minutes and 5,000 pesos later, I was directed by a man to the Brasilia bus ticket office. Using cash saved me 5,000 pesos, paying 25K pesos for my ticket back to Cartagena rather than the 30K I had paid for the trip to Santa Marta.
I've learned that the bus exterior gives no indication as to which company it belongs to. On each ticket receipt, the cashier at the ticket office hand writes the bus number for the corresponding trip. Though I traveled with Brasilia both ways, both buses had the markings of another bus company on its external facade. The bus numbers, however, were dead accurate.