When you activate an offer, you'll be shown the participating stores for that product near you. This means that you will only be able to redeem this cash back offer at one of the participating stores. If they aren't stores you want to shop at, you can choose not to activate that offer.
Any purchases made at stores that are not participating stores are unfortunately not eligible for cash back.
If you cannot find a product in a participating store or cannot purchase it for any reason, don't worry! The offer will expire if you do not upload a receipt before the Offer Expiry Date listed on the product page. The product will then move to your wishlist, and you will not be asked to review.