Yubin Hurikae

In Japan, the post office runs the finance business. It's usually not my problem. But when it comes to being payed dividends, I have to concern them because most corporates pay dividends in the form of the Yubin Hurikae which is the specific financial services provided by the post office. When I try to encash dividends, they require a lot of hanko stamps on the receipt. It makes no sence to me.