Primary Reson for missing orders is Plan exhausted, so make sure you have a proper plan and the system will run smoothly.
To see your plan see this image.
If you see you are using more orders than plan orders, you can click Change plan and select a plan which suits your order flow. If you do not find a suitable plan you can reach us on live chat for Custom Plan Requirement.
If your plan is not exhausted but still order is not present click the "Sync Order" button, it will sync all orders placed whine 24 hours.
If you want to pull order orders then please contact us on live chat. We will check and can offer you a one-time charge to pull these missing orders.