excess billing after cancellation

I am Ramasamy from Chennai India.  I applied for 15 days of free trial of Acrobat and then continued it for one month and then found it uselesss for my srvices. before  completion of one month I cancelled my subscription, but adobe continued charging me second monh inspite of my cancellation.again I canceelled the subscription online even then next month also adobe debited my account through auto debits.  finally this month they charged six times the subscription amount and I got the message my adobe facility is cancelled, I am a senior citizen the amount is huge loss for me,  Adobe uses complicated steps for cancellation especially for senior citizens like me to understand fearing further debits, I have blocked ny debit card  I request adobe to return the cancellation fee atleast.