To be fair to Sanparks (and I am a critic of them sometimes), their booking system is good, much better than it used to be. I have booked lots of accomm online from the UK it's the only way I book.

I used it when they were 'testing' it last year, it was good, but now it's rolled out, it's a big improvement.

The only thing they need to do, is allow those who have credit, to use that credit when booking online.
When I have requested refunds in the past, I have always been refunded on my credit card with 2 weeks. (international Credit Card refund). Those who don't get refunded without issues have usually not followed the correct process.