You cannot use MTN for an alarm GSM unit any longer.

Their are thousands of MTN Pay As You Go Simcards in GSM units all over the country. These are connected to alarm systems, gate motors, pumps and such like. The customers need to be able to check the balances from another phone or the app. MTN have made that impossible. USSD no longer works and the App uses an OTP. All the sim cards will have to change to Vodacom. MTN sucks.