Unable to book Visa appointment, it says wrong Receipt number

Hello,

I am trying to book a Visa interview appointment or my parents. I have paid the amount through online banking and when I started using the receipt number it shows the following error. I have double checked the amount and bank account number. Everything looks fine.
Can anyone help me to how I can get this resolved?

the error shown on the website is:

Visa%20fee%20error
"No valid record can be found for the entered receipt number. Please validate that your receipt number is correct and that you have paid the correct amount for the visa which you are applying for. "

Usually, it takes a day or two for the payment to reflect. Did you do the payment during banking hours ? Are you trying it after 1 to 2 days or same day ?

yes. The payment was successful. Also, its been a week since we paid. We tried few times. Its not accepting the receipt number.