From your description, what they did before was a Redirect. What they are doing now is a Forward. I'll have a dig around and see if I can see any changes, but I always thought what Netvigator offered was forwarding not redirection.
"Disaster" is surely rather too strong a word?
Edit: I don't see any changes in the mail config, so I guess they've just corrected their installation so that Forwarding does actually Forward rather than Redirect. Basing your email strategy on an error in the service is always going to be risky!
What is it that you need the original sender in the From: field for? Just filing? In that case with a decent email client you might be able to extract the details of who it was originally from and file that way.