I provide a service online for physical products. There really is no way for someone to be dissatisfied with the products we sell, only the shipping times, which we strive to ship the same day or next business day. We have had customers charge back just to be fraudsters, trying to get something for free. Here is how we stopped 99% of chargeback fraud: Hire a contract attorney, and have them write a contract your customers must agree to at checkout that says something along the lines of "I agree all sales are final, and that any charge back, or involvement of any third party will cause me to be in breach of contract." Then threaten them with a lawsuit for at least $5k for breach of contract and any other actionable claim if they do not reverse or cancel the charge back. If they do not respond to the email demanding them to cease and desist, we have the attorney who wrote the terms of service contact them via email, phone, and certified mail.
Works for me.