Unneccesary legal action taken against me

According to loan hub sa I've entered a 12 month contract with them in February 2017 whereby they would deduct a monthly instalment at each month end. They have taken legal action against me as I've refuse to pay them 2 months ago because according my to my knowledge the contract should have been cancelled in March 2018 after the 12 months. The legal firm is demanding the full outstanding balance for the 2 months that I have not paid them . Can you please help me regarding this.