Be prepared to invoke the cunning, logic etc. etc. to ascertain a reply email address. Sometimes this requires a detailed analysis of email headers. Where you invite people to submit queries etc., always point them to a form. Ask insufficient questions, and you risk exacerbating the above problems. Despite having a form, always publish a direct email address.
Many people refuse to fill out forms.
Others prefer to email directly. Check that the reply email address or phone number is, superficially at least, valid. If your address is incorrect or incomplete, we will NOT be able to process your request.