On Calle 7 facing the malecón, which is where the Fonce runs past the middle of San Gil and where the rafts go in. One of the older names in town.
The full San Gil list: rafting, caving in the Cueva del Indio, canyoning at the Juan Curí waterfall, paragliding over the Chicamocha canyon, bungee, and the parks. What separates the agencies here is guide experience and how old the helmets are, not the itinerary.
Two mobiles, and only the first is the WhatsApp line — check which one you are messaging.