Double Charged on Sixty60

I've made a purchase via Sixty60 on the 14th of May, the amount of R361 was reserved. On 15/5 the amount of R313.91 was charged to my credit card. That means the reserved amount of R361 should then be released. It is today the 29th of May, and that amount is still not released, which in essence means I've been charged double. I've lodged numerous complaints, nobody is getting back to me. The app and the actual delivery was tremendous, but the admin is a dog-show - I'm so disappointed. I've told all my friends and family about this wonderful service, and now regret doing it.