Problem with the products in the form

Good morning,
I’m having issues with a form that has always worked for us, but now it's not functioning properly. It's a form that includes products. When I select one, it doesn’t get added—or at least it doesn’t appear to be added—and if I fill out the form and submit it, the total amount is calculated by adding all the selected products. However, since nothing is visibly added, you can’t tell what you’re paying for. The total quantity isn’t shown either.
Would you be able to tell me what the problem might be?
This is the URL: https://www.colegiolareina.net/formacion-profesional/home/reserva-tu-plaza-de-formacion-profesional

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