If it's not much trouble, can you share with us a screenshot or image of what you see when trying to access the option to remove the channel? When you remove a channel, first determine if the channel has a subscription and whether that subscription is billed to your Roku account. If are subscribed through Roku Pay, the subscription must first be canceled before the channel can be removed from your Roku device.
Can you please provide us with more specific information about the issue you are experiencing? Are you being prompted with an error message? What troubleshooting steps have you taken so far to try to resolve the issue?
As a first step, you can try to remove the channel, update the Roku device by going to Settings > System > System update > Check now, restart your Roku device, and add back the channel.