Is Hyperli a ****?

I often buy goods online - mainly from Takealot, Loot or Amazon, successfully. I have fairly recently being sent mails from Hyperli with online 'specials'. I did order something a few months ago, and they were unable to supply. They refunded me about a month later. In the past month I tried again. Once again they were unable to supply the goods, blaming the supplier. My query about this took weeks to resolve and I was instructed to apply for a refund. I did so. They have now refused the refund due to a '7 day' delay in applying. They have offered me a voucher I do not want. I actually suspect they they are a **** as they receive money upfront for goods they cannot supply, and then take months to refund, other offer 'vouchers' (again later). this means that they sit with (and get interest on) YOUR money without supplying any goods. This is a ****!!