Hi there,
Welcome to the Community. It's important you're able to receive payments from your client. Rest assured, I'll be glad to guide you in the right direction.
To get started, I recommend having the client clear cache and cookies on their browser in case they're having browser-relate issues. Clearing cache and cookies is a great way to clean your browser allowing it to work more efficiently. Here's an article that shows you how to do that: How to clear cache and cookies. Give this a try and let me know how you make out.
I look forward to hearing back from you in the comments below. I'll be here.
