Am I too impatient?

Why is it so difficult for some people to reply email which stated clearly the sender needed some help or posted question? A simple acknowledgement on the receipt of the mail and letting the sender know whether you are able to help or not, will help to ease the mind of the requestor. Everyone knows it is politeness to answer people when being asked, and keeping quiet is considered rude. So why can't this rule be applied to mails?

Forwarded some questionnaire to Eu's teachers to help facilitate his reassessment with the clinic. No reply, no call, nothing. It's been three days. Even calling the school doesn't help. I'm getting edgy as the appointment date is drawing near. Am I the one here with problem or I should be more understanding? It's school holiday, maybe teachers do not need to check emails.