Refund within minutes & cooling off period

I am writing to see if I could request a refund for a recent subscription. I intended to sign up for a one-month trial, but I accidentally selected the annual plan. I cancelled the subscription within minutes of the transaction, but a refund was not automatically issued. Given that I cancelled immediately and am well within the 14-day "cooling-off" period, I would like to request a full refund of the annual fee.