FAILED ONLINE SHOPPING PAYMENT

I have been trying to make a payment to the United Kingdom Visa department for a week now. I have used my debit and credit card, received an OTP and the web site tells me that the payment was refused by the card provider (Master Card and Standard Bank?). This has happened dozens of times. I have phoned the call centre half a dozen times and spent hours on the phone. I have emailed a call centre person who promised to call me back and never did. I have been to my branch. No one seem able or willing to help me. It seems I will have to cancel my holiday due to this inability of Standard Bank to make a simple R 1 666 payment.