Incorrect seating information

My wife and I booked flights to Johannesburg to Singapore but could not find seats together on the flight. This was 1 month before the flight. We contacted Singapore airlines customer services to assist. Lebo from the airline advised that only a few seats were open for booking and more seats will be available 48 hours before the flight. It is now 48 hours before the flight and there are still no seats available for my wife and I to be seated next to each other