I want to know if there is a way to restore contents of permanently deleted users from my WordPress page.
None that don't involve a backup. If you have a backup, you'll have to do some work to restore only a certain user's data without resetting everything to that point. I'd say import the backup into an empty database, then copy data over either with SQL (
INSERT INTO wp_posts SELECT FROM otherdb.wp_posts WHERE post_author = ...) or with a script (getting the usermeta, posts and postmeta data).
If you don't have a backup, you might get somewhat lucky with caches (Google, Internet Archive), but recovering content from that will be more labor intensive and you will likely not get all the content.