Unable to cancel subscription

Help! I signed up for the Adobe Acrobat free trial, but was just charged for the first month since it expired. However, I am unable to cancel my subscription, as it is not under my subscriptions section.  I have not been able to get through to anyone regarding this matter. I was under the impression that because it was not listed under my subscriptions, I was not going to be charged, but I was wrong. I need guidance as to how to move forward.