I guess this is where the problem is. What’s stopping the seller from claiming he didn’t receive the payment? Or the buyer claiming he sent it, but didn’t?
That’s true, but I guess we could go back & forth for a while, since there will always be someone going the extra mile to “cheat the system” in terms of forging documents/proof. PayPal disputes comes down to the support rep handling the dispute, so yeah. Nothing in the payment world is waterproof, unfortunately.
I’ve actually looked into this years ago (setting up a payment processor service). The upfront costs are ridiculous, along with the legal aspect, and bank-like infrastructure you need on the back end for entities like VISA and MasterCard.