Refund request constantly being ignored

I canceled a ticket in good time and was told it will take between 7-21 days to get a refund. I have been following up on email and via telephone and the service is absolutely terrible, no response to any email I have sent, on the phone I am asked for my details and told that someone will respond to me and no one does, I follow up again on the phone and I am told the refunds department is not available I must call back after a certain time. It has been more than 21 days and Greyhound is not even responding, I would like clarity on whether Greyhound has any intentions to give me my refund or not and when I will get my money.