Hi! This MOSTLY worked for me. Same problem as everyone else...getting email to firstname@aol.com and dont have an aol account. So I did this:
In Gmail (NOT the mobile app):
1) Go to settings
2) Click ‘see all settings’
3) Select ‘Filters and Blocked Addresses’
4) ‘Create New Filter’
5) Fill in the ‘To’ line with the address that you are receiving email for, but which doesn’t belong to you.
6) Hit ‘Create Filter’
7) Select what you want done with it. I chose to ‘Delete it’ AND ‘Also apply to # matching conversations’.
8) Move on with life.
A few months later I am now getting email to firstnameminuslastletter@aol.com so now im facepalming but I just added that one to the blocked list as well...I guess Ill just keep adding emails to the growing list until someone comes up with a solution to block emails sent to all @aol accounts. BUT this solution will at least help.