Dont believe the hype about Hyperli

I attempted to make a purchase using the Hyperli online - but I have a for R300. Upon check out I could see the voucher being redeemed for the purchase but Hyperli charged the full amount on my credit card . So I had to pay Hyperli R400 instead of the R70 just for shipping that i was expecting i have tried writing to them and calling them but there has been no response from them - even on their own platform .