You go to your mailbox (outside, inside or wherever) collect your mail.
You take a seat and read your (mail or mails)?
You turn on your computer check your mail and find you have several waiting.
Do you read your email or emails.
If email stands for electronic mail -- why do people use the word emails? Would email be correct the same as mail is? No "S" ?
I vote for mail and email not mails and emails.