OnePlus
Set a Mobile Data Limit auf OnePlus
On OnePlus phones, mobile data does not stop by itself when you approach your monthly allowance. You have to enable Automatic Disconnection of Network Connections and define a fixed data limit that the system checks against your usage.
Once the limit is reached or exceeded, all mobile data connections are disconnected. They stay off until the billing cycle you configured resets, which is also when the counted usage returns to zero.
To set this up, go to Settings ➤ Wi-Fi & network ➤ Data usage ➤ Billing cycle ➤ Data limit. Enter the amount of data you want to allow and confirm with OK.
This setting only affects mobile data. Wi-Fi connections keep working normally even after the limit shuts off cellular data.
Use this if you want a hard stop to avoid extra charges. If you only want a heads-up before running out, check whether your billing cycle settings also let you configure a separate warning value below the actual limit.