Booking Credit Card Cancellation Fees

Scenario:

We are using Woocommerce Bookings to allow trainers to book and cancel personal training sessions. We charge them for each day booked. If they are allowed to cancel up to 24 hours beforehand, will we be charged a credit card transaction fee for the reservation and for the cancellation?

For example, we charge $100 to rent the space for a day. Normally we get $96.5 (stripe gets 3.5%.) If they cancel the reservation, I assume Woocommerce Booking reverses the charge. Who pays the reversal fees? Would the trainer get all $100 back? Do we pay $7? Etc.

Thanks! Paul

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