Complaint

I was at the checkers store Pavillion in Oakdene to book a flight ticket for my mom who is 75 years old. This was on the 4 May 2016.The flight was from Johannesburg to Durban. The lady at the tills.... her name if i am correct is Sindiswa, assisted me at the money market couter around 5h30. I specifaclly asked to book the flight for the afternoon for the 5 May. She checked on the system and advise that there was a flight for 05h50 that afternoon, she asked if she could book it i said to her yes. I explained that she cannot take the morning flight. the flight ticket was around 650. She then booked and printed and asked me to sign. I then gave the ticken to my mom and returned home. My mom was preparing to leave on the 5th to the airport i arranged a lift for her to be picked up at 3 so that she was an hour early at the airport. The driver then checked her ticket and realized that her flight reflected 04h50 in the morning. He immediately called me and said to me that my mom missed the flight it was not an afternoon flight.Flight no.(NPH NFX). I immediately called checkers to tell them that they had made a mistake. I spoke to the lady that assisted me. She confirmed with me on the phone that she remembers clearly that she had booked the flight for 5 in the afternoon, she said she will check and call me back. I waited for 30 minutes and she did not call. My mom was already at the airport in this time. I asked the driver to go to the mango counter and see what can be done, they asked him to call checkers and sort this out.I called back and spoke to the same lady she apologised immensely for making a mistake and said to me theres nothing they can do as i signed. She said that they cannot refund me. I then called the store manager he also said he will get back to me. he called me after 30 minutes to apologize for the ladies mistake and said to me that will reprimand her for making such a mistake. I asked him for a refund and he said he cannot give me a refund. I am horrified that i have been treated in this way. My mom is 75 years old she did not read the time on the slip. I signed on behalf of her. The fact the a mistake was made is the customer not right!!!.The store is holding me accountable because there was a signature on the slip. What about the mistake that the employee made, and she apologised for it. I have had to pay another 650 rand for a standby flight for my mom yesterday. I would like a refund considering that the lady made a mistake. Please help. I tried to get the number for the general manager of that store, it was in vein, the manager was not helpful at all. Regards Sharon Naidoo ***