How do they ensure that the email reaches the destination though? I have had emails never delivered to me, not due to my own fault but the service provider fil

How do they ensure that the email reaches the destination though? I have had emails never delivered to me, not due to my own fault but the service provider filtering it away before I could do anything. It is also dangerous to assume "use implies consent". I am sure there are other ways to ensure terms of use to be changed; if it is a web-application then one could only resume using it if the services were accepted before.