Glad you asked!
Your cash back money will be deposited onto your card between the 21st-28th day of the following month (e.g., if you earn cash back in May, the money will be deposited onto your card between June 21-28). Just make sure your primary card is updated to reflect your most recent and up to date credit card.
Some more important information:
Cancelled Cards: If the card you have on file with Rewards21 was cancelled, we will still be able to process your payment (in case the account still exists) despite the card being cancelled.
If your account is completely closed, please contact your former bank.