The real way that they are making all of the money is through the decentralized exchange that handles only Bitconnect tokens. First you have to buy their token (BCC) with BTC which raises the price. Then your money is locked in for 299 days if under $1000 and they only pay you out fiat. When you want to cash back out you have to buy their BCC token AGAIN and then you can sell that for BTC. On top of all the people re-investing which continually drives up the price, their token is ALSO tied to BTC price so as BTC goes up they also benefit... Here is a hypothetical scenario:

You buy 10 BCC tokens at $10 each so $100 total invested and they pay you $1 a day roughly. After 100 days you've made your $100 back BUT their token is now worth $30 because of all the reasons mentioned above. They now own $300 worth of their own tokens that you sold them netting their company $200. You figure since they ARE in fact paying and you will eventually get your original $100 back after 299 days you can safely re-invest. This will further drive up the price and so on and so forth.

As long as their price continues to rise they will have no problem paying out their "customers"