Reservation cancelation/reinstatement

I made a booking at the Radisson Blu Hotel in Umhlanga on the 24th April at around 16h00. Upon my arrival to check in, it was found that I had selected the wrong date (15 May). Unfortunately they couldn't accommodate me as they were fully booked. The next day I cancelled my booking but it said their would be no refund. I then proceeded to see if there would be an option for a refund and one did appear- which I selected. Once the cancellation had been done, I was informed that my refund would be R26, from the R2668 that I had laid. I contacted the hotel to inform them of my situation. They responded stating they have a zero refund policy and there was nothing they could do. I further pleaded with them asking them to please reinstate my booking if a full refund wasn't possible. They responded saying, "I'm the one that cancelled the booking, so there is nothing they can do". They then informed me if I have any further queries, I must contact bookings.com directly. I contacted bookings.com and they said their hands were tied and it was in the hands of the Radisson Blu. I really understand the no cancelation policy for dates closer to the check-in date, but in my situation when the booking was in +/- 21 days time, in all my life I had never encountered such. My booking was made in error as I tried to Beek for the 24th April and somehow may was selected. Worst case scenario, if you don't want to refund me, then please reinstate my booking. R2668 is a lot of money and it would be really unfair to punish someone in such a cruel manner.