Yeah, the customers support seems very shy. 😆 That seems to be couple of issues affecting you. Take a look here for possible one step solution (or few steps, at least). 😉 Let's hope this will work for you.
For more deep discussion what's Dropbox and how it works, take a look here. 🙂 Awareness of details could prevent further complications. Seems you have got in overquota where everything else is result of it.