From the Fraud Center:
If your advocates share their referral code on popular coupon-sharing sites, ReferralCandy can now detect that and inform you in your Fraud Center. You can then ban the advocates and disqualify any referrals they have made. When you ban an advocate, all referred purchases within the review period will be automatically disqualified. For more information about our fraud prevention program, click here
Here are some top tips on how coupons code misuse can be prevented:
Setting an expiry date for your discount coupons.
Periodically change the coupon codes that are used in your campaigns.
Ensuring discount coupon amounts are set in a way that you still benefit from every purchase made.
Using the Promo Link option (not available for Shopify) of the Friend Offer to point referred friends to a URL that you host, which:
Gates a unique single-use coupon code that you generate. This is linked to the email address they need to enter to obtain it and can be delivered via email or shown directly on the page.
Shows all referred friends from a single referral link the same code that you generate. This gives you the ability to deactivate a single code from your platform if fraud is detected.
If your eCommerce platform supports it, limit the use of referral coupons to new customers only*. This is the most effective method, but platforms vary by capability so please check with your eCommerce platform provider.
*This can be done by checking the email address or shipping address of the customer against your database of past customers. If it happens to be an existing customer, display a message on the checkout screen indicating that the referral coupon only applies to new customers and that a smaller discount amount will be applied instead.
For the Shopify platform, you can run a check against your existing customers by following the steps here.
Any usage restrictions should also be stated clearly in the referral invite emails and landing pages that customers and their friends see so that they are not surprised by it during checkout.