Ineffective Website Booking

I have tried for 2 days now to make bookings from Johannesburg to Bangkok and to Hong Kong and back to Johannesburg. I put in the dates, the site displays a number of options. I chose my preferred option. I continue with uploading all the requested information.For the past two days, the response I keep getting after inserting my details including the payment option is that the Flight is not available. I even phoned the Call Centre and they then tell me that the flight is not available. Yet the website still displays that the flights are available. Don't use the site to make bookings