As the submission on your installation isn't linked to an email address I don't know how they would contact you.
However, you can use the Restore option in Quarantine, that sends it back to the original location, if it is still detected Avast will alert again.
You don't mention when this alert occurred if it was on an on demand scan (in which case Avast should alert right away) or when you tried to run it, in which case you would have to run it again.