Page is getting redirected even after I delete the plugin

This plugin redirects by using auth_redirect which uses wp_redirect to do the actual redirect. wp_redirect uses a 302 by default and should not be cached anywhere.

Deactivating and/or deleting the plugin stops the redirecting. If not some caching layer could be at work. You could try to purge all caching you have on your website and server (if any) and purge your browser cache.