firstname.lastname (at) gmail and firstnamelastname (at) gmail
are the same address.
People also get very confused about + in addresses.
Literally the only time I've gotten something that was for another person is when someone else with my exact name purchased something medical and they emailed the receipt to "firstnamelastname@gmail.com". It turns out that if gmail receives an email in that format and all they find is "firstname.lastname@gmail.com", they'll go ahead and stuff it into that inbox.
I was able to track the person down, call them, explain what happened, forward the email to them, and delete it.
My name isn't super uncommon, but for whatever reason I don't get those sorts of emails.