How to put a temporary hold on customer's money?

[TammyTE]

Let's say my customer is charged $200 for my product. But if they send me their core I will give them a refund of $50. Thus only charging them $150. I would give them 15 days to get the core shipped to me.  Is there a way to hold $50 of their total $200 payment to me until I receive the core?  If I receive it then I don't take the $50. If I don't receive their core then I go ahead and keep the $50.

I realize I can just issue a refund if I receive the core, but wouldn't this be tedious and cost more in fees?  I am looking for the simplest way possible. Maybe even a button the customer would click as an option when checking out. Thanks!

[kernowlass]

No you can't do that.

Refunds are pretty quick, you just click on the refund option in the details of the transaction and if you have funds in your paypal account balance its instant.

When you refund you get the part-fee you paid when you received the payment back again apart from a few cents processing fee.