@Luaina
Hello! I'm glad to hear that you're anticipating growth for your app. I'm sorry to hear that you're experiencing issues with linking your card. Let's try to resolve this together.
Could you please check if your internet connection is stable and if you're using a supported browser? Also, please ensure that you're entering the correct card details and that your card is not expired or blocked for online transactions.
If everything seems fine on your end, there might be a temporary issue with our system. In that case, I would recommend trying again after a short while. If the problem persists, please reach out to our support team for further assistance.
If you need any more help or have any other questions, feel free to ask.