What are the immigration office hours during the holiday season in Thailand?

@Kelly *****

there is no such thing as a 7 day extension.

You can try applying for any extension when you don't qualify, and then may receive a 7 day "application denied, you must leave the country" stamp. The immigration officer does not have to accept your application, and it's generally advised to avoid this if possible as it can affect future applications for visas or extensions or make it more difficult to enter the country.