Payment solution

I have a restaurant reservations site, which helps customers book an event at a restaurant. When a customer makes a reservation, we take a refundable security deposit from the customer. After the event is held, we reimburse the amount. We get a booking fees from the restaurant, as a percentage of the total tab.

I am in the process of implementing a payment system, like Paypal or a merchant account. Paypal says that they will drop us if the number of refunds are above 5% they will drop us.

I am just trying to figure out the most logical way to get this implemented.

Thanks!

This is well beyond my area of experience, but perhaps you could do something similar to a hotel reservation...

Rather than actually charging an amount when the reservation is made, you could simply take the credentials required to make a charge, and do one of two things:

1. Schedule a future payment (perhaps the day after the reservation date), and then if the deposit is going to be refunded, simply cancel the scheduled payment.
2. If the first option is not possible, just wait until after the event date, and if the deposit is not to be "refunded", then schedule the necessary payment.