Prevent submission from going through until payment is collected

I created a plugin to work with BirchPress Scheduler. My plugin basically captures a user’s cc info and then allows the site owner to charge them if they don’t show up for their appointment. Everything is working, I’m just trying to integrate it with the BirchPress plugin.

Ideally, I’m going to have a popup that comes up when a user hits ‘submit’ after scheduling an appointment. I’m trying to use the birchschedule_view_bookingform_validate_booking_info hook to delay the submission until after the payment goes through. Do you know of a way I can use that hook to only have the appointment go through if the payment works? I can set a variable $is_set and check it that way, but when I do that, it’s not actually checking it when I hook into birchschedule_view_bookingform_validate_booking_info. Do you have a suggestion how I could check that?