I haven't used the voucher yet, because when I wanted to use it at the end, the officer told me that if I wanted to use a traveloka voucher, I had to say it at the beginning. How do I know if I have to say at the beginning, after the clerk typed on a computer and it can't be canceled then I pay in cash. I told the clerk if they had to inform or ask what they were using at the beginning of the payment. I am very disappointed