Prepaid subscriber extra free days

Is it possible to give all prepaid subscriber extra free days (probably 2 or 3 days) when their balance reach minimum before they have been blocked, so that they can use the internet without charging them. If I change Minimum balance to negative will this serve may purpose?


Yes, minimal balance exactly for that.

Days will not be free, but this will cover non blocking when balance will go to zero.

How about if we need free days for prepaid subscribers.