Accidental Subscription Charge With Prezi

My name is Isak and I am a student with significant debt and very limited financial means. I started a free 7‑day trial of the Prezi Plus yearly subscription on 21 October. My intention was only to try the service, as I cannot afford an expensive yearly plan. As far as I remember, I cancelled the subscription within the trial period because of my financial situation. However, on 28 November I was still charged approximately $285 for the yearly subscription, which was very surprising and stressful for me. Since I am a broke student in debt and this amount is a serious burden, I kindly and respectfully request a refund of this charge and the cancellation of the Prezi Plus yearly subscription linked to my account. The invoice number for this payment is INV05467087. I would be very grateful if you could review this situation with understanding and help me with a refund.