considering the warning about responding by telephone (page 2) can I respond by email? or 'letter' only?
Do you have an official e-mail address that you may respond to? If they provided an e-mail address, I would guess that e-mail
might be sufficient, as the trail could be adequately and completely documented. But unless you have an email address from them, or you sent an email to them and they confirmed receipt of your email by the proper department, I would suggest you stick to mail (preferably trackable).