Amazon claim they made a payment but the payee's bank shows no evidence of it. There is this thing called MT103 which allows a payer to prove that they did in

Amazon claim they made a payment but the payee's bank shows no evidence of it. There is this thing called MT103 which allows a payer to prove that they did in fact make a payment. That should resolve things, right? But no, Amazon refuses to supply it, and says that's final. WTF?