Unwanted postal mail from Cox

Can Cox please stop sending me postal mail marked "Important Customer Information" which only contains unsolicited offers to upgrade or add more services?  I get 2 or 3 pieces of mail from Cox each month and this misleading "Important Customer Information" makes it appear that there is something wrong with my account.  I realize that the purpose of this "Important Customer Information" is to trick people into opening the mail and I think this is a poor and unethical way to do business.