Sierra Club They refuse to stop soliciting for money Oakland CA

We have made more than 20 attempts to try to get the Sierra Club to stop soliciting for money.  We have done this through email, regular mail and telephone calls.  They refuse.  This may not seem like a big problem.  Except that we are not the only ones they are doing this to. 

They are doing it to susceptible people who are elderly or have dementia.  They will do anything to just get more money, no matter who they prey upon.  If you once give them any money, they will not stop until you give them more and more.