My response to that is, yes you can. If someone were to do those things to me, that is exactly what I would do. The first time someone swore at me on the phone they would get a warning that if they did it again I would hang up. If they did it again I would then hang up. If I received a high pressure, rude email I would email back stating that I would not discuss any kind of deal with someone using those tactics and that if this person did not want to treat me with respect I would set my email to not accept anything from the offending address. If the next email continued in the same way the first one left off I would delete it and block this email address.
There is no need to take any kind of abuse from anyone.