Bookings disappearing as staying on line with FlySafair

As a frequent flyer - even when choices of airlines were available - I would choose FlySafair above competitors. It is sad to see how they are relentless in their pricing now that no other airline is available. After 37minutes waiting to be assisted I also had to pay an additional R3000 after buying a ticket for R2100 because I needed to add a 6 year old and there was no seat available on the flight. I was literally looking at the screen where it showed seat availability but apparently while waiting to be assisted the flight was fully booked. I honestly feel that this could have been handled better. I also suggest FlySafair revisit their approach to Pensioners travelling with grandchildren and the total process of making use of privileges ie Sanlam Reality. I think this process should receive definate attention to simplify bookings in this regard.