Billing Issue of Acrobatpro cancellation

I was on free trial for Acrobat Pro service, and it's the annual subsciption but the bill is paid monthly. I cancelled it before th esubscription ends (before 1 year). And now I need to pay 50% fee of the rest billings. They send me the email to pay the bill and it's one-time session, and I forgot to click on it. Now I want to pay it since I feel uneasy whether they will charge me later on, but I can't find the icon or any notification since that one-time click. What should I do?