Negligent Advice and terrible service

Mango's staff is very unfriendly and not unhelpful. My mum who is a sick old lady was turned away by the Representative at the counter even though we checked her in the day before! Mango's booking terms and conditions of carriage; our check-in counters and bag drop queues close promptly 40 minutes before departure time and the boarding gates 15 minutes prior for already checked-in passengers’.My mum was at the Mango line counter 40 minutes prior to take off .The agent was busy checking the weight of the bags when she received a call 39 minutes prior to departure. The representative informed my mum that there is nothing she can do and that she needs to book another flight which will cost an additional R3200? My mum was 24 minutes early to board the flight as boarding gates close 15 minutes to take off. Based on the negligent advice from Mango's staff and my mum not being a regular flyer she really believed that she missed her flight. She proceeded to call me as I was still on the airport premise. We queried the matter with Shabnam Dhansay | Team Leader at Mango guest services who apologised for their staff's Negligent advice but offered no assistance with refunding the tickets or providing a credit note? We requested they do an investigation by looking at the camera footage. She apologized for the mistake but offered no further help in further investigating the matter so we could be refunded. My mum has subsequently missed her doctors appointment which had to be rescheduled. The anxiety caused by this experience has put more strain on my mum who is currently receiving treatment. Why do consumer's suffer a loss as a result of the terrible advice given by Mango and their failure to provide good customer service? I’m sure that an esteemed airline like Mango does not intend to treat passengers unfairly and try to make a buck off pensioners? I hope that this does not happen to anyone else so please be careful.