Not really sure why you want a 30 day refund, should you not ask for an eleven month refund as you wanted only a one month subscription rather than a one year?
Additionnally did you not read the terms of the offer made to you before you made the payment? How could you miss the price difference between one year and one month does puzzles me.
One more lesson in life for you.
Now go to the help and support at the very bottom of this page and click on Help & Support and from ther you can contact chess.com and ask for a refund.
I was offered a 10 day trial that after the free period was supposed to charge me only 1 month. It charged me for 1 year. I was hoping I could get the 30 day refund because I have no desire for one whole year!