The anti malware tools you mention are for a local PC, using them to check the issue did not come from a hacked machine (and stolen credentials) is required but not sufficient.
Still no replies to
“Did you properly reinstall your site by deleting all contents in your hosting space, and then uploading a fresh, up-to-date WordPress ?
Are all your plugins and your theme Enigma also up to date ? Is your hosting environment (Apache or NGnix server, MySQL database, PHP version ?) also up to date and secure ? Did you change all your access codes including FTP and SSH access on your local PC ?”
If i delete all content and data then all my SEO work is lost. so please suggest any other way to fix this…
Your SEO positions will in no way be lost if you temporarily delete contents and put your site back online even if it was suspended for 24h (use a plugin that lets you specify the site is under maintenance, 503 response). Getting your contents back online in a safe environment will on the opposite ensure that Google does not one day detect your site as hacked, and prevents people from visiting. Such a blacklisting from the main search engine may be much harder to get out of and prejudicial to your SEO efforts.