How to recover from navigation damage on wordpress site

It happened once to have my word-press site down because somebody hack it. It was the first time to have my site down because somebody hacked it. the navigation on my site was not working probably. What make it bad is that I was not have any backup of my site. Having the risk of loosing my site’s content was like a nightmare for me.
The issue was basically the navigation was not working as well as if I try to use a valid URL it was not navigating to the correct page as well. Control panel was not accessible because of the same issue.
Then I start thinking what might bring the Navigation down. Then I start thinking what might be corrupted on my site. The good news I was using a customized theme so all what I did is deleting the theme I have on my site by using FTP client and restore it again. This solve the issue and I start putting strategy to backup my site and make sure to have a base to recover my site without even have any possibility of loosing my site’s contents. The mistake I have is having the theme folder with write permission for anonymous access. This security permission was required by a plugin. So I took that plugin out from my site and re-set the correct security permission on the theme folder.