Crazy penalty for canceling a booking over 6 months in adnvace and within 5 hours of making booking

Booked accommodation today the 1st April 2019 at 12:30 for a few nights in a Stellenbosch. I also made several bookings for Cape Town only to find out from my wife that I shouldn’t have booked in Stellenbosch as we already have accommodation. I called 5 hours later to ask for this to be cancelled (within 7 days) and I was told that I will be penalized 50% of the full cost. This is crazy as no one will be out of pocket and the property can go straight back on the market especially when the booking is only for October. This is shocking and surely can’t be in accordance to the CPA!