Just to inform you that today [19 July] and for the next couple of days, MTN are carrying out upgrades to their signal towers. This will result in some loss of signal strength to the SIM cards in your alarm system.
Once the power has been restored you may receive a 'SIM card restore' message. This is nothing to worry about and the alarm will continue to work as normal.
Thanks to Pegeia Neighbourhood Watch for this information.