Some hotels will send fax for outside persons. Did this before, hotel initially refused and wouldn't discuss, then I offered 200Baht to reception manager, fax sent 1 minute later.
I had to do this letter for OZ DVA six months ago. Concernd about the return date I called DVA, got transferred quickly to correct section, DVA lady quickly said e.mail is fine.
Sent it by e.mail, 2 days later an e.mail from DVA confirming they had received my scanned proof of life form and confirmied it was accepted.
So maybe (repeat maybe) C'link will accept by e.mail, perhaps call then on the toll fee number to check, and if OK get a specific e.mail address.