After logging in, you will be redirected to the

settings

page, where you can see the Account button at the top right.

https://desk.zoho.in/galleryDocuments/edbsne4c27e6f50e1500d12f048c536e3352264706ca19f4931db021a896cf719f21b2cb38bd5ad6c6cd046c1d6ab46b170f86c318646671e0a7e68b2a13502b71266?inline=true

Then, you can find the Account button on the left sidebar, after clicking on that button you can see this screen.

https://desk.zoho.in/galleryDocuments/edbsne4c27e6f50e1500d12f048c536e3352201bc1f161a5cda132ac68c2bec12f3831ab835259aac97779125e0a126aa2e80c50b182388258aacdc170d78205f01e6?inline=true

Here, you can find the Cancel Current Plan button. After clicking on the button, you can cancel a plan.