Cancel accidental subscription and refund

Hello, I am currently a student and I was accidentally subscribed to the annual plan for Creative Cloud. I initially signed up for a free trial to try out Adobe Illustrator in March 2019 for my school project but Adobe has been charging me US$20/month for five months without my knowledge. I have not opened the application since the one time use nor logged in to use any other adobe apps.

I only discovered that I was on the subscription when my card had insufficient funds and was asked to update my payment details. The cost of the subscription is very high for me in my current situation. I now need to terminate my subscription and I would sincerely appreciate if I could get a refund for the last several months. I would be immensely grateful If anyone can help with my situation! Thank you.