I followed up every day and finally received a response from them on 8/30/17 stating they could resell my tickets for me for $100 to $150. I had paid $635. Since they had not responded in a timely manner and the rescheduled concert was for the next day, I informed them I expected a full refund (I could have sold the tickets for much more than $150, given the time). They then advised me that was policy (which I have added below).
They have not responded to further queries from me and I find this to be not only extremely poor customer service but bad policy on their part.
Their policy: "If your event has been cancelled you will be refunded the total order amount, except for the delivery fee. If your event has been rescheduled, your tickets will be honored for the rescheduled date and time. You should contact the ticket seller supplying your ticket order for information about cancelled event refunds and new event postponement dates."