Somasundaram is mistaken. I did not say your account was hacked. I said your address was hijacked. That means that someone else is just using your address as the sending address for junk mail, but they're using a mail system of their own to send it. Because spammers do not use completely validated lists of recipient addresses, some fraction of their messages will be undeliverable and the receiving mail server will complain by sending a non-delivery report to what it believes is the sender: your address. Your account has not likely been compromised, but in this, Somasundaram is completely correct: it would be prudent, nontheless, to log into your mail service using a web browser and change your password to something strong.
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