When you sign up to 28 you are agreeing to a recurring payment, you’ll see this on the sign up page where we state that your payment will automatically renew each month or quarter after you join. Before proceeding with the sign up, you must also agree to the terms and conditions, which have similar statements about 28 automatically renewing each month. As you agreed to this in the sign up process, we are unfortunately unable to refund you.
Make sure you cancel your subscription via the 'account' page of the website if you no longer wish to be a 28er and want to stop being charged.