Tonycobweb: Here comes local differences in place of course. But i found that being friendly is a good way, as the people that you will talk with are pretty much never the ones that done you wrong.
You should have answer in 24h or try again. Call/email/chat or what ever other ways are possible, you will most likely get a different person in every way and you want to find someone that care about his or hers job that actually care to help you get things straight.
Being irritated or angry can work in some situations, but most likely it will deter the person from helping. No one likes being pushed around, especially if they are not self at fault...