It could well be because it is the Christmas period and they have been busy with family and friends that they haven't replied to your email.  Alternatively they may not have received your email at all or it could be languishing in a spam folder thanks to an overzealous filter.

I tend to prefer using Site Mail myself for contacting vendors as you can see if they have read your communication or not and it circumvents the vagaries of email servers and spam software.