No, Instacart shoppers cannot block customers. However, Instacart provides a number of tools and resources to help shoppers manage customer interactions, including the ability to report customer abuse or inappropriate behavior to Instacart's support team. If a shopper experiences any issues with a customer, they can contact Instacart's support team for assistance. The support team can then take appropriate action, such as disabling the customer's account or offering support and resources to the shopper.