Not Returning Deposit after Booking Cancellation

We Booked a Garden Wedding at Letaba River Lodge on the 18th January 2015 and we Paid the Deposit of 50%, R5000 on the 15th February 2015. This Garden wedding was Planned to be on the 19th December 2015 and Costed R10000 for 5 Hours (08H00 to 13H00). On August 2015 we then cancelled this wedding Garden Wedding due to Family wanted us to do this matrimonial at the Church. This communication was done via Telephonic and Email. According to the Letaba River Lodge Cancellation Policy: 3 Months before stay date:90% of deposit is refundable, 1 Month before stay date: 60% of deposit is refundable,2 Weeks before stay date:30% of deposit is refundable and 1 Week before stay date:% of deposit is refundable. We tried means of communicating with Isabel the Manager ***) in regards to this and she promised to refund us but this never materialised.