With the booked priceplan you pay a flat-fee for storage (Uploads) and traffic (Downloads). For further details please check our price plans).
But in the basic configuration your platform isn’t blocking your command if you need more storage or your users take more outgoing traffic. It will be charged in the next month on a pay-per-use basis.
If you want to prevent this, the Owner of a platform can set a tick in the box at "Prevent Uploads when Storage Limit is reached" under "Settings" > "Cost Control".