Overbooking and delayed Refund - Unprofessional

The Carnivore restaurant was booked for our company year end function for the 4th Dec 2015. This booking was made in October and payment was made on the 02/11/2015. On the 1st of Dec (3days before function) we received a call from Michelle to say they had mistakenly overbooked the restaurant on that day and asked us to either change our date or take the evening booking after we informed MIchelle that this was not possible as our clients were already informed that our office would be closed on that day, we were left with no choice but to cancel and ask for a refund to get a new venue which needed 100% payment. Michelle assured me that we would get a refund in time to pay for the other venue. This did not happen, we sent follow up emails and calls to Michelle to no avail. A week later we are still waiting to be refunded by Carnivore. This is appaulling from a so called well established restaurant, and their failure to speedily refund us shows how much they don't care even if it was their mistakes. They can be sure that all our associates,staff and their families will know what kind of service is received from Carnivore. Leaves a lot to be desired.