It's taken me many weeks to get to the bottom of the Cashback World Scam, but this is how I think it operates:

In brief:
Cashback World are buying Giftcards from National Retailers (in particular Love2Shop) at a discount and then re-selling them back to their members at full price. They give a percentage of that profit back to the members through 'cashback' and keep the rest.
Then they pretend that major Retailers are their merchants, so they can entice in the Small/Medium sized business owners, who pay them vast sums (up to £1050) to join.

Full post is here:
https://taratalkstoday.blogspot.com/...card-scam.html