In fact I have every client agree with me from the beginning that our emails serve as the written terms our agreements when we both agree in writing. And I ask them to always save every email they send me and every email they receive from me, so that we will both have a written trail of correspondence to refer to when (not if) there are any misunderstandings.
This system has served me well for many many years, so for someone to make an all-encompassing claim that no one reads emails is just plain ridiculous.