Sometimes customers may call claiming they were having problems placing orders. It's important to know how the system behaves so you can differentiate between a possible anomoly with the system and when the user may not be following directions. One important item is to note exactly what information is required in order to proceed in placing an order.
When a user is prompted to input his personal/billing information, the following data is required or else the purchase will be interrupted and the user will be told he has not specified valid data. Sometimes users do not pay attention and inadvertently leave something blank so it's important to check to make sure the following things are specified:
Example: It would not be terribly rare to have a user complain that he/she entered "a valid e-mail" address and the system told them it was not valid. Many times what a user thinks is a valid e-mail, and what is really valid are two different things. For example, many AOL users think of their screen name as their e-mail - and if they are simply sending e-mail to another aol user, it will work, but when dealing with non-aol users on the Internet, they must alter their screen name to be compatible with Internet e-mail name conventions, which includes not having spaces and specifying an @domain.com suffix. Please be sure to qualify the user's information to make sure they're not misled.