Step-by-step guide to creating a blacklist of fraudulent customers

Samuel Freitas · 2026-10-07

Creating a blacklist of fraudulent customers is essential to protect your e-commerce business and reduce financial risks. Here are the steps to follow:

Defining criteria for adding customers to the blacklist

1. Identifying Suspicious Behavior: List behaviors that indicate fraud, such as multiple orders in a short period, orders using different credit cards, or suspicious IP addresses.

1. Purchase Amount: Set a purchase amount threshold that, if exceeded, leads to a customer being added to the blacklist. For example, orders over R$ 1.500,00 should be reviewed.

1. Return and Refund History: Customers with a high number of returns or refund requests may be candidates for the blacklist.

1. Verify Information: Use validation tools to confirm the authenticity of customer details, such as their address and CPF.

Methods for regularly updating the list

1. Monthly Reviews: Schedule a monthly review of the blacklist to add new cases and remove customers who no longer pose a risk after a period of time.

1. Automation: Use machine learning algorithms that can identify behavior patterns and update the list automatically.

1. Team Feedback: Create a process for the team to report suspicious cases that aren't on the blacklist yet.

Integration with CRM systems

1. Data Import and Export: Make sure the blacklist can be easily imported into and exported from the CRM system you use.

1. Real-Time Alerts: Set up alerts to notify the sales team when a blacklisted customer tries to make another purchase.

1. Interaction History: Keep a record of interactions with blacklisted customers to make future decisions easier.

Internal communication about blacklisted customers

1. Regular Reports: Send monthly reports to the entire team with information about blacklisted customers and the reason they were added.

1. Training: Hold regular training sessions so everyone understands why the blacklist matters and how to use it properly.

1. Communication Channel: Create a dedicated channel where the team can discuss suspicious cases and share information about fraud.

Examples of effective blacklist management

1. Reviewing Old Cases: Review previous cases that were added to the blacklist and check whether the criteria were applied correctly.

1. Trends Analysis: Use FreeSpy to monitor fraud trends in ads and understand how they could impact your customer list.

1. Customer Feedback: In some cases, it may be useful to contact blacklisted customers to understand their motivations and adjust your criteria if needed.

What's your current rate of customers being added to your blacklist?