Refund still not received.. 3 months later

I canceled my bus tickets at the end of November 2023 and was told that the refund process takes 21 days. Up until today I still haven't been refunded. I constantly need to follow-up to hear the same old story about a backlog on refunds. How in the world is it possible for refund backlog to still not be resolved 3 months later. And it seems like there is only ONE person handling refunds and still no response from that one person. They can't even put a person in contact with a manager. So how does one resolve this issue.