If you exceed your subscribed bandwidth allowance, your service continues without interruption. Any additional data transfer is billed at the standard per-GB rate, which is deducted from your prepay balance.
There is no hard cap or throttling applied. Your servers continue operating at full network speed regardless of how much bandwidth you have used. This ensures that traffic spikes do not disrupt your services.
To manage costs, monitor your bandwidth usage through the control panel and consider using a private VLAN for server-to-server traffic, which is free.