I understand your need to arrange prepayments for events like these, but unfortunately, sending credit card information in this way is not considered a safe method by card issuers, so I will use not this method.
Please understand that I and my family are guests at the hotel on Christmas Eve and we already have paid for a Luxury King room and expect our buffet dinner reservation to be confirmed conveniently.
We live in Bangkok, and if you need my prepayment for the buffet, I can suggest that I rather show up at the Sofitel and pay in person if there is no secure way of making reservations online. We will also bring our child and will appreciate having a child seat by our table.
Please provide your instructions.