Bad Experience at Khulala Airlines Check In

I am totally disappointed at the service received at the check in at OR Tambo on Christmas morning. Ticket was booked online 2 months prior. Flight to PE was scheduled at 6:05 am I reached check in at 5:15 And was told was too late to check in. I was than made to pay R1400 for a 799 ticket.. A totally disappointing way to start the Christmas Morning.. Did I really miss my flight and had to re- book a for a new seat.. 15 minutes costed me double than what I initially paid. Very disheartened!! Won't fly with the airline again and would advise family and friends not too..