We agreed that I pay 6 months rental and the 7th month for penalty, and the is communication on the emails, and on the records of their calls! But now they are telling me that I owe them the penalty or cancellation fee, and of wich they say the 7th month

We agreed that I pay 6 months rental and the 7th month for penalty, and the is communication on the emails, and on the records of their calls! But now they are telling me that I owe them the penalty or cancellation fee, and of wich they say the 7th month money they deducted was for installment not the cancelation fee as agreed earlier. Kindly assist please