delete complete sit and build it again

2 days ago i hair a freelancer from this website, i though he really did his job, today i find that the same problem is still there . 1- i want someone to delete the complete site because it send SPAM Emails, 2- install WordPress fresh and updated . 3- make sure that backup the email account 4- guarantee the work for 2 days i already do the backup in case something happens . need to stop this spam right now . i just suspend the account to make sure i stop the spam .