cancellation of contract

I have had a few bad experiences with Virgin Active in the last year. I took out a 1 year contract last year in May. I went in about 4 months ago to pay the balance outstanding as I knew the contract would be done and I asked the consultant if after this I owe them anything she responded no ( and I dealt with more than one as I went into the gym to make my payments). Now I get a message saying i am 3 months in arrears. I am not paying this amount fro a contract that should no longer be valid as it is past a year and I have not made use of this membership within the last few months. I need this contract cancelled which should have been over after the year.