Malware – PHPmailer

Hi,
One of my domains were temporarily suspended yesterday night because suspicion malware in the path: …wp-bootstrap-starter/PHPMailer/src/PHPMailer.php
“The page suspiciously emits many emails and is probably hacked. FTP and File-manager access are still possible”
The site can now only be accessed through c-panel filemanger/FTP.
Do you have any tips what can be done to fix the issue? Except create new passwords etc for admin.
Thanks