Thetha-thetha taking money but not responding

Thetha-thetha is a company that sells vouchers and vending machines for airtime and electricity. By creating an account you transfer money to them and then purchase vouchers. This worked fine for some time. I recently transferred money to my account which reflects as their site is still active. However when I try purchase an airtime voucher I get the error that the stock is not available. Multiple mails to their info mail are ignored. When calling their number the automated voice states that the number is un-obtainable. My money is therefore gone. Yet they still accept transfers and their site remains active.