Email received - "Alert: An email addressed to you has been quarantined"

[#1]

I received this email yesterday:
On 2015-01-29 12:50, Email Alerting Service wrote:
    Dear Plusnet Customer,
    You are receiving this mail because you have an active virus-scanning
    service, and either a banned file extension or an email containing
    a virus has been sent to your address.
    The mail was sent to you from:
    *      "Samantha Naquin" <bhykolxwq@[I've deleted this].com.au>
    The subject line of the mail received was:
    *      [-SPAM-] BACS Transfer : Remittance for JSAG376GBP
    In order to protect you, this email has been stored on our servers
    and quarantined.  If you wish to retrieve this, please send an
    email to unquarantine@quarantine.plus.com containing the following information;
    ----------------------- SUPPORT INFORMATION ----------------------
    Quarantine-Id: 017958acafde2ff9fd5b0f94bcea1d1e44649
    Message-Id: <K201G3CB.7783528@[I've deleted this].com.au>
    To: [my email address]
    ----------------------- SUPPORT INFORMATION ----------------------
    It should be possible to reply to this mail to retrieve your email,
    as long as your email application includes this entire message in
    the reply.
    Kind Regards,
    Customer Support.

I've done a forum search and there are several references coming up from 2008ish time but nothing recently.
Would someone please advise why I've had this email - is this really the first time since I joined several years ago that a virus-carrying email has been sent to me?

[#2]

I haven't had one for ages either
One possibility is that the spam filtering service looks at them before the virus checker and discards the obvious spam which may well be the ones which contain viruses

[#3]

It's also some time since I had a quarantine warning, probably when "courier" related spam messages were popular.
I have received a number of "payment" receipts that usually (but not always) go into spam including some to an address external to Plusnet (that Plusnet will not be aware of).
I don't have "discard obvious spam" selected.

[#4]

I got one of those on Wednesday  (purporting to be a fax),  it was also tagged as spam.  It's also the first one i've seen in some time  (a couple of years or more)
My assumption was that generally these are picked up as obvious spam and discarded (which is why they appear so infrequently),  but these didn't quite match that criteria so made it further, at which point the virus checking stopped it.
In my instance,  given the 'To' email address used,  it's not going to be anything other than virus laden spam,  so I ignored the message!

[#5]

Virus quarantining has been broken for a while. I reported a problem with it last September (ref: 82743). Turns out there was a typo in one of the procedures. No idea how long it's been like that for

[#6]

I had two or three of these today - I did wonder why they'd suddenly appeared after so long!

[#7]

I, too, have been receiving a significant number of these quarantined notifications and how welcome this safeguard from PlusNet is!  Well done, I say!
I use unique email addresses allocated to most of my non-personal emails and it is interesting to note the companies that have, or have had, sloppily managed Contact Lists.
Currently emails using the address I allocated to uswitch are being used by a hacker/s, others remind me of early security failures, eg Adobe and, indeed PlusNet when some Contacts were lost, quite a few years ago and I left the pinched addresses out of interest.
The "repaired" service will make it so much easier to monitor the offenders.
Regards....

[#8]

I have had 3-4 or of these emails from MAAF who I have a just account with. The first for many along year.