Cancellation which was turned to be an upgrade

I called to cancel 1 of my contract and was transferred to the retainment department ,the lady was busy offer some other deals and i told her that the reason for my call was to cancel the contract . She offer me another deal and i told her that i need to think about and i need her to send me the details to read through. To my surprise the contract was upgraded and now they want me to be stuck on a new 24 months