Never give out a real email address to those types of people. That was a big mistake, for anyone you don’t know. Either makeup an email address, or give them someone else’s email address (like, perhaps, the Dean’s).
It would be nice, in addition to the huge religion-promoting material sent by my son’s college, they would send atheism information as well. At least they admit that they have only four chaplains - Catholic, Christian (specifically Episcopal at this point in time), Jewish, and Muslim), but give a huge list of other places of worship that welcome college students.
Spitting on someone is a crime. I agree that I would consider reporting the incident to campus police if they continue to bother you. If you have emails from them, that can prove which organization is bothering you.