If you're receiving spam supposedly from this domain, your mail server is probably not setup to handle SPF records and DKIM authentication. Both SPF and DKIM are anti-spam measures to ensure that the sending server and/or sender is authorized to send mail for that domain. Without both the sending and recieving parties setup for at least one of these, it is quite easy to spoof a domain. The default installation for most mail servers do not include any anti-spam measurements and must be done manually. Mail for this domain is handled by Google, so the message header will indicate it came from Google. If it doesn't, your mail server is not setup correctly. If it does, you're welcome to derectly reply to the message with a copy of the header and it'll be looked into.
"Those who would give up Essential Liberty to purchase a little Temporary Safety, deserve neither Liberty nor Safety." -- letter from the Assembly to the Governor of Pennsylvania, 1755/11/15