Flights on website cannot be booked

I wanted to book a multi-city flight for 2 adults to fly from Joburg to London & return from Rome to Joburg. I found this flight option on SAA website at a reasonable price, started the booking process, waiting for the \payment"stage when the website hung. I called the call centre & told the booking had been processed & I was sent the bookings by email. When i tried to pay I received an error message that the booking was not \""E-ticketable\"". I called again & advised to call the next day after 10am as the international desk was not open. I called after 10am & was told the booking had been cancelled as the flight couldn't be booked as it involved another carrier. The flight option was STILL available on SAA website. I have always heard what a state SAA is in but have flown with them domestically and thought it would be great to fly with them internationally. I am absolutely amazed that the website can be so bad that it allows someone to go through all the stages of booking but that it is impossible to book. I wasted a good few hours doing the booking and making 3 phone calls to try & process the payment. Very unhappy with SAA!"""