Virtual credit card payment

I would like to address a question about the VAT number of the client. In my country I should declare the VAT number of my clients. What can I do if the client

I HAVE NOT ADD ANY BANK ACCOUNT OR PAYPAL. I WOULD LIKE TO KNOW WHERE THE MONEY OF MY RESERVATIONS GO

I HAVE TRIED TO PUT MY PERSONAL VAT NUMBER AT THE FINANCIAL MENU AND IT SHOWS ME THAT IT IS INVALID. IS IT CONNECTED WITH THE FACT THAT MY BANK ACCOUNT CHANGES