Request for refund for accidental adobe pro subscription.

Hi, to whom it may concern, I have accidentally subscribed for adobe pro a month ago, as I thought I had cancelled my 7 day free trial however I just now am seeing that I was charged £20.84 last month, and this month aswell however the payment was declined for this month. I was not aware that I had subscribed, or that I was charged last month. I also thought I had cancelled my free trial but apparently not. As you can already tell I do not have the funds to pay the monthly trial as my payment has been declined, and I cannot cancel the subscription either because it tells me I need to sort out the issue with my card first. Please allow me to get a refund from last months payment and to cancel the subscription from now on aswell. It would be greatly appreciated, thank you.