Yeah, phone or at list email is a must. Although sometimes people call from Canada or overseas and leave their number expecting you to call them back. (And don't even mention they are out of the country.) Then you get a big bill a month later so that they could chat with you about cards because you called them back without a foreign calling plan. When calling from another country, the decent thing to do is to mention where you are calling from and give them an email address that they can respond to for free. Fortunately, the abuse rarely happens, but it certainly gets your attention when it does!