Do you have your payment settings to authorize only, and capture later? If so, there is still an authorization window that limits when the funds can be captured. If you are using Shopify Payments, then the authorization window is 7 days, meaning you must capture the payments within this timeframe. Other gateways may provide different lengths of time for which the payments may be captured.
You can read more about payment authorization on Shopify here.
Victor | Shopify Social Care