I usually tell people that I received payment, or I will confirm address and tell them when I plan to ship. When I'm buying something I will often confirm payment and confirm ship date so I know when to expect the package.
If they sound peeved about answering a simple question like that then don't do business with them anymore, I wouldn't.
If they sound peeved about answering a simple question like that then don't do business with them anymore, I wouldn't.