standard "phising" email. about a billion of them are sent out a minute from various sources all round the world, to every email addy possible.. (as well as lists of known emails, think aaronAAarvark@aaa.com, aaronBAarvark@aaa.com and so on).. your ISP does filter them out, but a few get through from time to time. 

blocking originators won't work, since they are forged anyway. 

just delete and ignore...