story
The reason they do this is to hold on to your money as long as possible with the outside hope that you'll just go away and they get away with theft.
It's bad enough with larger companies where the people you're working with may not actually be the people who are writing the checks, but at a small company like this it is unacceptable.
Assuming the story is true, the CEO agreed to pay then decided that she didn't want to pay anymore. To accomplish this she's doing her best to get the designer to give up and go away.
How is this acceptable behavior? Again I realize it's common, but it's flat out dishonorable.