I debated with my peers that we can use the word emails when referring to more than one and it would be grammatically right.
But most of them said since we don't say we received mails today, similarly we won't say we received emails .
Quick advice please.
Emails and email are both correct plurals, but each has its own context. It depends on whether or not you are using it as a countable or uncountable noun.
You can use email as an uncountable noun, just like mail. For example, "I received lots of email today" or "John sends me too much stupid chain email". But, you cannot use email as a countable noun. For example, "I have five email" makes as much sense as "I have five mail".
Emails
You can use emails as a countable noun, just like letters. Originally, email was always uncountable, just like mail. But over time, largely due to the ubiquity of use, pieces of email or email messages (and similar phrases) were shortened, and simplified to just emails.
For example: "I have five emails" or "Kevin sends me too many emails". (Contrast that last one with "Kevin sends me too much email".)
Of course, you can still use emails in some contexts where email is also acceptable ("I received lots of emails today"), but it does have a slightly different meaning (compare to "I received lots of email messages today") because you are using a countable versus uncountable noun.
Dan Bron's comment (above) that e-mail/email at its inception was treated as a mass noun is correct—and so is Kristina Lopez's comment (above) that e-mail/email is widely applied today not just to the medium of electronic mail but to individual messages sent and received in that medium.
For many years the technology magazines where I worked enforced a strict house rule: e-mail (and later email) referred to "electronic mail" as a mode of communication, and individual messages had to be termed "e-mail [or email] messages." But three or four years ago, the overwhelming weight of popular usage prevailed, and we began to accept the use of email as a singular noun that could take an indefinite article, and emails as a plural noun—both referring to individual messages.
It is probably not coincidental that other forms of electronic communication receive similar treatment in popular (and some publishing) usage: a text and texts for "a text message" and "text messages," respectively; and an IM and IMs for "an instant messaging message" and "instant messaging messages" (as I recall, people used to avoid "instant messaging message" by conflating the technology with the individual message to produce "instant message").
At publishing houses, the proper handling of "an e-mail [or email]" versus "an e-mail [or email] message" remains a house style issue—there is no universally agreed-upon preference. If you are beholden to no one's style guide, you are free to use the wording that you like better. But the overall tendency, I believe, is toward accepting an email and emails as collapsed forms of "an electronic mail message" and "electronic mail messages."
Your peers are not wrong.Technically, email appears to be correct since the word e-mail stands for electronic mail.
It can be used as a verb (meaning sent by email) or as a noun (meaning a message sent by email). To make the noun plural, some writers prefer to use the term “email messages.”
However, I am going to say you are both correct.
Email is the medium of communication. Messages would be the plural of what you receive through said medium.
It is correct, as Nick2253 explains. But it can also sound awkward and (sound) wrong to the ear. Depending on the context it may be appropriate to choose a different word with a nicer plural.
As long as it's not a legal deposition, the fact that it is an email may not be particularly significant and you can substitute messages, responses, transmissions, epistles, love-letters, documents, etc.
