Dear hannah98kw,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
I’m sorry to hear that you’re experiencing issues with a channel you deleted and then restored however, you can't access it through SharePoint nor have access to the files. I would like to express my sincere apologies for any inconvenience this may have caused you.
Could you please check to see if you can find the channel site under Deleted sites in the SharePoint Admin Center? To access it, you will require administrator rights or need to ask your Administrator to help perform these steps:
If you don’t find the channel site under Deleted sites, you can also check under Active sites and click on the site. After that, let me know if you managed to access the site or if you are getting any errors, and I will further assist you.
We appreciate your understanding that sometimes the initial suggestions may not resolve the problem very soon. However, we can work together to narrow down and resolve the situation. If you are stuck anywhere or get an error while performing the above suggestions, you can provide me with screenshot. You add the screenshot using the forum word editor feature:
Thank you for your understanding and cooperation. We appreciate your patience as we work to resolve this issue.
Sincerely,
Ralph Chawatama | Microsoft Community Moderator