Account holders at 20Twenty, the Internet arm of Saambou Bank, have been left high and dry together with the rest of Saambou's investors and account holders after the bank was put under curatorship at the weekend.
Christo Davel, chief executive of 20Twenty, said the company had been instructed to close its website and call centre on Saturday afternoon.
The Internet banking concept was the brainchild of Davel, a Cape Town businessman. Because of the difficulty and length of time it takes to obtain a banking licence, 20Twenty looked for a banking partner in the venture.
Saambou subsequently took up a 65 percent stake in 20Twenty.
20Twenty opened for business in July, offering a single account (a credit card, current account and savings account rolled into one) with a single MasterCard-branded card.
The account offers low transaction costs, low interest rates on money you owe the bank, and high interest rates on money you keep in your account.
A freeze was placed on all withdrawals from Saambou and because the funds of 20Twenty customers are, in terms of its banking licence, in Saambou's coffers, 20Twenty customers were also denied access to their money.
Since Saturday customers have been unable to pay for goods and services with their 20Twenty cards, and have not been able to make any withdrawals from automatic teller machines.
Some customers had to abandon trolley-loads of groceries at supermarkets tills because their 20Twenty cards could not be used for payment.
Christo Wiese, the Registrar of Banks, has been reported as saying that Saambou's 380 000 depositors will be able to access the first R4 000 in their accounts when the bank re-opens its doors.
Deposits are on average R27 000.
Saambou branches were closed on Monday and are expected to remain closed for a few days. Wiese did not say when the bank would re-open its doors.
20Twenty posted a statement on its website on Tuesday from the curator, John Louw of KPMG, explaining the immediate effects of the curatorship.
*Economists have urged Saambou customers who are unable to pay their bills as a result of the bank's difficulties to approach their creditors and explain the situation.