Give them a link to the terms of service and say "please direct me to the language in your terms of service to that effect." Follow up with "as a paying prime member, I insist on compensation for Amazons failure to meet their guarantee". This has always worked for me. Some reps have pressed back when I insisted on two instances of compensation for one order with two late packages. I replied "I have no sympathy for a multi-million dollar company that fails to meet its obligations." Have gotten several months of prime and gift cards through chat in this way.