It seems like your online store is experiencing a form of fraudulent activity known as "card testing" or "carding." This is a common technique used by scammers to test stolen credit card information before using it for larger purchases or selling it on the dark web. These scammers typically automate the process by using bots or scripts to place multiple orders with different names and fake email addresses.

While it can be challenging to completely stop this type of activity, there are several steps you can take to mitigate the impact and protect your business:

1. Implement fraud prevention tools: Consider using fraud prevention services or tools that can help detect and block suspicious transactions. These tools use various parameters to analyze the risk associated with each order, such as IP address, device fingerprinting, and historical transaction data.

2. Set up transaction limits: By setting limits on the number of transactions allowed per customer, per day, or per hour, you can reduce the impact of mass fraudulent orders. For example, if you notice a sudden surge in orders, you can temporarily limit the number of purchases per customer to prevent further abuse.

3. Enable CAPTCHA or reCAPTCHA: Implementing CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) or reCAPTCHA on your checkout page can help differentiate between human users and bots. This additional step can deter automated attacks and reduce the number of fraudulent orders.

4. Monitor and analyze order patterns: Regularly review your order data to identify any suspicious patterns or trends. Look for orders with similar characteristics, such as multiple orders from the same IP address or a high number of failed transactions within a short time frame. This analysis can help you identify potential fraudulent activity and take necessary actions.

5. Contact your payment gateway provider: Reach out to your payment gateway provider and inform them about the fraudulent activity you are experiencing. They may have additional fraud prevention measures or recommendations specific to their platform.

6. Strengthen your website security: Ensure that your website and e-commerce platform are up to date with the latest security patches and plugins. Regularly monitor your site for any vulnerabilities and consider using a web application firewall (WAF) to protect against common attacks.

7. Educate your customers: Inform your customers about the importance of secure online transactions and encourage them to use strong passwords, enable two-factor authentication, and regularly monitor their credit card statements for any unauthorized charges. By raising awareness, you can help prevent potential victims from falling into the hands of scammers.

Remember, it is crucial to consult with a cybersecurity professional or your e-commerce platform provider for specific advice tailored to your situation.