Extend AWS promotional credit

As a startup, we got a one-year, $15,000 AWS promotional credit, and we used it to build our product on it. As we are reaching the one-year deadline, and we still have no funding/customers, I contacted the AWS team and asked for an extension. They responded with: "it's not possible to extend credit at this time." I was wondering if anyone knows of any way we can extend the deadline, or get a new one. Thanks!