RTD does not charge your account until your product is ready to ship. Orders are filled twice every month, usually around the 10th and the 20th.
When you place your order with a debit card, your account will show an immediate pre-authorization hold on funds, but the actual charge will not go through until the processing date (near or after the 10th or 20th depending on when you placed your order). This pre-authorization hold will only remain on your account between 24 hours and 7 days after the sale completes - depending on your bank's policy.
When the order is actually processed, your account will be charged the price of your order. If your transaction is declined, your order will automatically cancel. If the order cancels no funds are withdrawn, and so no refund or credit is given.
If you have any questions about how this works with your specific account, please contact your bank directly.