Two main methods are;
Different proof you can collect are;
Has several seller accounts
Directs buyers to other pages
Suspicious ratings
Typically, unauthorized sellers will increase their fake customer reviews so that they can be ahead of authorized sellers’ listings. They can do this by buying their own products and leaving reviews. So, if you come across a reseller with your products, make sure to check the ratings to see if anything appears to be fake or suspicious. If you do, use it as evidence.
Several brand listings
Misleading information
Conclusion