Can't cancel subscription

Hi, I am asking for help because I cannot cancel my subscription. I am a student and I honestly did not plan or prepare for a paid plan. I only intended to use the free trial to work on a school project, but I forgot that my subscription was extended. I thought I was still within the cancellation period, but the system keeps asking me to update my payment details. That payment method is my only option, so I am unable to proceed with the cancellation. I have also tried reaching out for help via the virtual assistant and typing out “AGENT”, but I have not received a response yet. I sincerely hope you can understand my situation and help me resolve this. Thank you.