sounds like perfect grounds for a chargeback to me. Company offered a full refund via one of its Agents, company then refused to honour that offer, time to make your bank force them to refund you.

Just because you use AI for customer service doesn't mean you don't have to honour its offers to customers. Air Canada recently lost a case where its AI offered a discount to a customer but then refused to offer it "IRL"

https://www.forbes.com/sites/marisagarcia/2024/02/19/what-ai...