Ragnor: I think the obvious may have been overlooked here...
1) Email is not a 100% reliable method of communication, you may think it is but it isn't. Emails can and do disapear into the ether.
2) Basically there is no gaurantee they even got the email and no way for you to check they did
3) If the email was badly worded it could have easily been spam filtered
Conventionally true, however, one has to question when they get an automated helpdesk ticket system response?