I just noticed in "oldmotcrossers" post for RM pistons that his e-mails have bounced back, I too have had this problem with e-mails a few times over the years.
I have had a lot of emails that I have replied to that have bounced back as either non existing address or they bounce back because the server thinks I'm spam. I asked an IT guy once what to do & he said that I should contact the guy & tell him I'm not spam, well "derrr" how do I contact him to tell him this if I can't get through.
I had a dozen or so of these early in the year & I have another at the moment that doesn't bounce back but doesn't appear to be going through either despite about six attempts & he keeps asking why don't I reply.
Iv'e noticed here a few times that guys have complained about not getting any answers from companies, it may be because of a similar problem.
The internet is a great means of comunication but it's not perfect so it would be wise to also send another means of contact with your e-mails, be it fax, phone or address.