Double booking

We booked accommodation through RoomsForAfrica at the end of October and made a payment. On 2nd of December ( a month later) we contacted them via email to find out if everything is still in order to which they rep**** yes, and we made a second payment. Just to be notified a day later that the holiday unit is not available due to double booking. Did it take them a month to find out that it has already been booked? And now we are battling to get our refund from them. The agreement was not cancelled by me, but by there incompetency to follow up on bookings. I am not the first or only person complaining on HelloPeter about RoomsForAfrica cancelling agreements due to double bookings. Maybe they should start doing damage control and find the culprit who's not doing their job. Every time I call them, they tell me that someone will call me back, which they never do. This was the first time we used RoomsForAfrica and defenatily the last time.