No, your electricity will not be shut off; however, you should endeavour to clear the debt prior to conversion, otherwise the bill will be transferred to the prepayment system. If the transfer occurs, on subsequent purchase of electricity, a portion of your payment will be deducted and used to reduce the arrears.
Yes, your electricity will be shut off (disconnected) when your credit runs out. However, the meter will give a warning when the credit falls below 20Kwhrs. When faced with this situation it is advisable to top up your credit so as to avoid disconnection.