Security and privacy

The workaround you mentioned (setting supportpage as a redirect to your homepage) creates its own problems (if that is the only change you make). Primarily, the result is that you now have a support link live in your site, which will redirect all legitimate students, teachers etc who try to click on it straight back to the homepage. Usually they are only going to be clicking that when they have a problem, so combining that with an infinite loop of being redirected to the homepage when they try to reach out for assistance results in an fairly frustrating experience. If there is no other way to avoid this, I would suggest that someone with access to the relevant code removes the link from the footer menu, in addition to you setting the supportpage. While not helping users who need support, at least removing the menu item prevents further frustration from a non-working feature, while setting the supportpage will lock down the contact form page so it cannot be accessed directly.

If we can troubleshoot those earlier items though and there's some other solution, hopefully removing it completely can be avoided. One final option is also investigating whether you can set up spam protection on your inbox, so you can still effectively support legitimate emails, but avoid the others - though this is just a final though, and I don't want to assume which services are/aren't available to any specific host.