For VTC Pay payment method there aren’t any test data available, but you can see how it works with the payment flow given below.
VTC Pay Payment Flow
The customer enters his Email Address (the below page can be skipped by sending the parameter in the payment request).
The customer has to choose his preferred payment method from the list.
After choosing the payment method the customer logs in to his VTC Pay account by using his account number and password.
The customer will receive a a code via text message to his phone number which he needs to enter to confirm the payment.
The customer receives a message that the payment was successfully processed.
Upon completion of the payment flow, the customer is redirected back to your ReturnURL.