BA Customer Service Agent quoted minimal cancellation fee. BA pays nothing

Due to unforeseen circumstances I couldn't board a flight from jnb to heathrow on 28th June 2017.

Ba was fully booked the following 2 evenings flights. When I queried the cost to cancel this leg of the trip I was quoted an R800 cancellation fee. When the refund came through BA only refunded the taxes.

I have called, emailed and filled in forms online since mid July trying to get this resolved. Eventually they have come back saying they won't take responsibility for the mistake their agent made on the phone and won't refund any more money.

In what world do you not refund your customer when your staff have provided mis information? Disgusted and won't be flying them again!