How do you withdraw your funds from National Lottery? Frustration

I received a message to withdraw any balance I have at the National Lottery before 25 May 2026. I visited their website and completed the withdrawal form, ensuring I had entered a banking profile and other details. After filling out the form, there is a button labelled "Send Request". However, this button is greyed out and unresponsive. I tried to call their call centre a number of times and spent many minutes in the queue, but no one answered.