Mail attachment quarantined by Trend Micro

Hi,

I am having trouble with an email attachment that I received. I use an icloud email account and am accessing it from the Mail app on my iPhone. The attachment is a PDF file but when I try to open it, the file only contains this message:

"Trend Micro Antivirus has quarantined the previously attached file, if this is a genuine file please contact Consortium Group to have it unblocked."

I do not have any sort of antivirus protection on my phone or on any of my devices. It would seem odd to me if the sender's antivirus would quarantine an outgoing message. So I am struggling to work out where the message was quarantined.

The attachment has also been renamed to:

"TREND_MICRO_ANTIVIRUS_QUARANTINED_ATTACHMENT.TXT"

I don't really want to ask the sender to resend the email because this is rather important and I don't want to seem incompetent and cause a hassle. So that would be a last resort but I may end up with the same result...

I don't know who Consortium Group are or how to contact them. Do they actually have the pre-quarantined attachment that I am after or do they just modify their filters to allow it to be resent correctly?

Any ideas on how to retrieve the attachment? Any clue as to at what stage and why it was quarantined?

Cheers.