Not taking tokens once depleted units completely

Infuriatingly bad product design City Power installed a new Voltex unit (the keypad is marked D120KP, I don't know the model of the actual meter). The new unit is connected to the meter via a standard wall socket. 1) The new meter does not sound a warning alarm when electricity balance is low 2) My balance depleted in the middle of the night, leaving me without power for some hours 3) The internal battery of the keypad is useless, so it was completely dead by the time I woke up and tried to enter a token 4) I am now in possession of a useless token, unable to charge the meter, which requires power, which requires me to charge the meter

I must be missing something, because I can't believe that Voltex would intentionally design. Unfortunately I can't tell, because of course there is no online documentation available, and no helpline (unless you count City Power's atrocious reference number dispensing system).