Need A Lead

On a weekly basis, I receive a sealed envelope with a postage paid card inside. This card wants me to fill in personal information and return it to them via the postal system. They make it sound like this is the only way to obtain info about Medicare. I want to stop this mail from going out to anyone. We are constantly being told not to give out such info, yet this company asks that we send it through the mail for anyone to read. They should at least tell you that your info will be given to others AND provide a return envelop that can't be seen through.