Claim I agreed to a online yellow page subscription

Told me I owed them $599.99 and if need a verification number from them to cancel the account so I would not be billed for another year.  I could not ask any questions, could only answer yes to their questions.  When their "Quanlity Control" person got on the line I tried to ask her a question and she hung up.  The guy who called said they were located in Ft. Mills, SC.