Samsung
Change Mobile Data Usage Limit auf Samsung
Samsung phones ship with a built-in data limit inside the Connections settings. This value is not tied to your carrier plan and can sit far below or above what you actually pay for. Once mobile data usage reaches that number, the system disables the mobile connection automatically until the next billing cycle starts.
This safeguard lives inside the Data usage menu, under Billing cycle and data warning. It works independently from anything your carrier tracks, so changing it only affects what your phone monitors locally, not what shows up on your bill.
To adjust it, open Settings ➔ Connections ➔ Data usage ➔ Billing cycle and data warning ➔ Data limit. Enter the new value and confirm with Set.
If you only want a heads-up instead of a hard cutoff, look for the data warning option in the same menu rather than raising the limit itself. Setting the limit too high removes its purpose as a safeguard against surprise data charges, so match it closely to your actual plan allowance.