Contacting SANParks is impossible

I tried to raise a query regarding a reservation in one of the national parks using the SANParks email addressed advertise on its website. The email is returned undelivered as "the recipients inbox is over the limit / full" and no emails are accepted. I tried the email route as it is impossible to reach SANParks reservations by telephone. What is the point of advertising an email address as a means of contact if no-one at SANParks reservations bothers to read through and respond to emails?