If you did not reboot your Roku after removing the channel, it wasn't really removed. If you did reboot before adding it back in, and the channel continue to not load, then you need to contact whomever provides that channel. Most likely it is the television station themselves, although they likely contract the work out. But they are who you have to contact. Roku has no control over 3rd party channels, and except for The Roku Channel and Roku Media Player, they are all 3rd party channels.
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee, just another user.