If it passed 48 hours (or depending on the merchant's condition) and you still not received the Cashback. You will need to submit a Missing Cashback request for every order that's missing.
Here's where you can do it:
1) On the mobile app, click on the user icon and search for "Report Missing Cashback".
2) On the website, click on "Cashback Overview" and you will see a red button for "Report Missing Cashback".
IMPORTANT: Missing Cashback submissions must be within 30 days from the purchase date. Any submissions past the specified time are invalid and will not be investigated by the merchant.