Here's a random idea I got this morning. I don't have a tech/dev background so it's not something I have an interest in starting or looking further into — just dumping it here for your thoughts.
A service like trust pilot, but for businesses. A service where businesses and brands review customers as a way of forewarning other businesses/brands about fraudulent customer accounts, excessive returns, and just shitty customers in general. When a customer places suspicious orders, harasses your company or leaves bad reviews for no reason, you can track their history of interaction with other businesses so you can plan your next course of action. I see complaints all the time from business owners being maliciously abused by their customers – be it by fraudulent transactions, excess entitlement, the list goes on…
If you can build a payment gateway and have customers sign in to their profile to process their payment (kind of like Paypal) then you, as the brand, can leave a review on the customer (1-5 stars.) This will help differentiate fraudulent, and manipulative customers from honest and trustworthy customers. The customer will also have an incentive to be genuine whilst interacting with you, to protect their own reputation.
Fiverr and Upwork have a rating system for both the client and the freelancer, why can't businesses have this same luxury? In today's day and age, the "customer is always right" philosophy does not always apply.