Sending Email

My account was attacked sucessfully by someone who set up a sub account, changed my signature and I found out when I could not send emails.  I got it all fixed with deleting the sub, changing my password and security questions.   In a few days it happened again though they did not set up new sub account.  BUT in the meantime I cannot send emails from any devise.  I can receive fine.  Verizon Technical has been at a loss to help me.  Any ideas?  Thank you.