I have the same problem. There are about 5-7 active idiots using “firstlast@gmail.com” and I get them all.
Suspect their real email is something like “firstlast10” or “firstlest” (minor spelling variant). Not sure if they deliberately misspell their email or are just stupid.
For a while really thought amount was compromised.
Slowly I realized they are just idiots and assholes. They don’t always pay bills, buy $100 T-shirts, own crappy vehicles, and seem to conduct business with people who don’t verify email either.
Even once got into an argument with an idiot persistently claiming he owned “firstlast.com” (as I replied to a thread using such from my email server. I’ve owned the domain for 20+ years). He was a certifiable idiot, also by trade…
I also get a lot of “mcafee subscription” PayPal scam mails. Also have seen a lot of spam real subscription accounts created using the same email but with wildly different names. Suspect it is fraudsters testing credit cards.
The sheer number of big name companies that don’t validate emails surprises me…