You will need to submit a Missing Cashback request for every order that's missing.
Here's where you can do it ("Report a Missing Cashback"):
1) On the mobile app, go to the “Human” icon (at the top-right) and choose “Report Missing Cashback”
2) On the website, go to the “Question Mark” icon (at the top-right) and choose “Missing Cashback”
IMPORTANT: Missing Cashback submissions must be within 30 days from purchase date. Any submissions past the specified time is invalid and will not be investigated by the merchant.