Why BlackBerry - ed. disables the data service?

Question

blackberry

BlackBerry automatically turns off data service after my balance goes to zero.

After replenishing the balance, you need to enable data transfer in the settings (otherwise the browser does not work, turn on data transfer!). I looked in the manual for what such a switch could be connected with and did not find anything except:
Turning the data service on and off, setting roaming parameters
docs.blackberry.com/en/smartphone_users/deliverables/21074/Turn_on_or_turn_off_data_service_60_1068389_11.jsp

But I was not roaming … all the time on your home network.