Up here, all you have to do is go through the return procedure on Amazon, they send you a page to print, you wrap up the blouses and tape the printed page onto the package and take it to the post office. The post office takes it at no charge. As soon as the post office processes the package you get your refund into your charge card - you don’t even have to wait for Amazon to get the package back.
Maybe someone can confirm if it works the same for your area.