I've worked on marketplaces before, though not the most technical job you can get in the industry, you must execute on the product side your the operational wheels will literally fall off. Even this app, it's not a two way marketplace, as it is a three way: end users, clients, and you as the operations team. It can also be very difficult to get flywheel effects going, but that's a problem for a different day :)
Anyway, it always surprises me that non-technical founders try to enter a field where the are unskilled in the core competencies (software/sales/marketing), then outsource that competency to someone with no vested interest in the outcome of the project. There's a reason tech companies don't outsource the tech, and that's because you want extremely tight integration of decision making and technical knowledge.
Additionally, I'm surprised the marketing spend was so low. An infinitely better plan would have been for one person to build a BE/website that works on mobile, another to sell it to some clients with fun activities, and spend as much money as possible on targeted marketing. That, and not trying to sell a travel application in the middle of the largest travel industry recession since 9/11.